Presentation is loading. Please wait.

Presentation is loading. Please wait.

Marine Weather Course NOAA National Weather Service Baltimore/Washington Forecast Office.

Similar presentations


Presentation on theme: "Marine Weather Course NOAA National Weather Service Baltimore/Washington Forecast Office."— Presentation transcript:

1 Marine Weather Course NOAA National Weather Service Baltimore/Washington Forecast Office

2 Part I Outline National Weather Service Introduction National Weather Service Introduction Baltimore/Washington Forecast Office Operations and Marine Area Baltimore/Washington Forecast Office Operations and Marine Area Key Marine Products and Hazards Key Marine Products and Hazards Marine Observation and Forecast Information Marine Observation and Forecast Information Marine Safety Marine Safety Marine Reporting Marine Reporting

3 NWS Service Delivery Facilities

4 WFO Area of Responsibility

5 Operations & Services ConvectiveConvective - Tornado & Severe Thunderstorm Tropical SystemsTropical Systems - Hurricanes & Tropical Storms Non-PrecipitableNon-Precipitable - Heat Waves - High Wind - Wind Chill/Excessive Cold HydrologicalHydrological - Flash Floods - River Floods - Small Stream & Tributaries Winter StormsWinter Storms Coastal FloodingCoastal Flooding Wildfire (Red Flag)Wildfire (Red Flag) Spruce Knob, Pendleton County, WV Elevation 4,861 feet

6 Operations & Services (cont.) ForecastsForecasts - Public - Marine - Aviation - Fire Weather - River Support ServicesSupport Services - Homeland Security Data CollectionData Collection - Climate - Cooperative Observers

7 Marine Area

8 Key Marine Products Coastal Waters Forecast (CWFLWX) Coastal Waters Forecast (CWFLWX) Special Marine Warnings (SMWLWX) Special Marine Warnings (SMWLWX) Marine Weather Statements (MWSLWX) Marine Weather Statements (MWSLWX) Nowcasts (NOWLWX) Nowcasts (NOWLWX)

9 Coastal Waters Forecast Issued a minimum of 4 times / day Issued a minimum of 4 times / day Amendments issued as necessary Amendments issued as necessary Each CWF goes out 5 days, with each period covering 12 hours Each CWF goes out 5 days, with each period covering 12 hours Used by small pleasure boaters to large commercial transport ships. Used by small pleasure boaters to large commercial transport ships.

10 Coastal Waters ForecastElements: Synopsis – Short, concise Synopsis – Short, concise Headlines of long duration hazards: Advisories, Watches, Warnings Headlines of long duration hazards: Advisories, Watches, Warnings Wind – from 8 compass points, in knots (kt) Wind – from 8 compass points, in knots (kt) Waves – wave heights, in feet (ft) Waves – wave heights, in feet (ft) Weather – thunderstorms, rain, snow and fog (significant visibility reduction) Weather – thunderstorms, rain, snow and fog (significant visibility reduction)

11 Long Duration Hazards Small Craft Advisory: (Tidal Potomac and Chesapeake Bay) -- the following conditions are occurring or expected to begin within the first 3 forecast periods: Sustained winds kt Sustained winds kt Frequent gusts kt Frequent gusts kt (frequent refers to lasting > 2 hours) Waves 4 ft Waves 4 ft

12 Long Duration Hazards Gale Warning: (Tidal Potomac and Chesapeake Bay) -- the following conditions are occurring or expected to begin within the first 3 forecast periods: Sustained winds kt Sustained winds kt Frequent gusts kt Frequent gusts kt

13 Long Duration Hazards Storm Warning: (Tidal Potomac and Chesapeake Bay) -- the following conditions are occurring or expected to begin within the first 3 forecast periods: Sustained winds kt Sustained winds kt Frequent gusts kt Frequent gusts kt

14 Long Duration Hazards Hurricane Force Wind Warning: (Tidal Potomac and Chesapeake Bay) -- the following conditions are occurring or expected to begin within the first 3 forecast periods: Sustained winds 64 kt or greater Sustained winds 64 kt or greater Frequent gusts 64 kt or greater Frequent gusts 64 kt or greater Not associated with a tropical system Not associated with a tropical system

15 Tropical Hazards Tropical Watches/Warnings Initiated by National Hurricane Center in Miami Initiated by National Hurricane Center in Miami nhc.noaa.gov nhc.noaa.gov Tropical Storm (sustained winds 34 to 63 kt / 39 to 73 mph) Tropical Storm (sustained winds 34 to 63 kt / 39 to 73 mph) Hurricane (sustained winds > 64 kt / > 74 mph) Hurricane (sustained winds > 64 kt / > 74 mph) Isabel, 2003

16 Convective Hazards Severe Local Storm Watches Initiated by Storm Prediction Center in Norman, OK Initiated by Storm Prediction Center in Norman, OK spc.noaa.gov spc.noaa.gov Tornado Watch Tornado Watch Severe Thunderstorm Watch Severe Thunderstorm Watch

17 Coastal Waters ForecastANZ /X.EXT.KLWX.SC.Y T1200Z T2200Z/ TIDAL POTOMAC FROM KEY BRIDGE TO INDIAN HEAD- TIDAL POTOMAC FROM INDIAN HEAD TO COBB ISLAND- 337 AM EDT SUN OCT SMALL CRAFT ADVISORY NOW IN EFFECT FROM 6 AM EDT THIS MORNING THROUGH THIS AFTERNOON....TODAY...NW WINDS 15 TO 20 KT. WAVES 1 TO 2 FT..TONIGHT...E WINDS 5 TO 10 KT. WAVES 1 FT OR LESS..MON...NE WINDS 5 TO 10 KT. WAVES 1 FT OR LESS. A CHANCE OF SHOWERS..MON NIGHT...N WINDS 10 TO 15 KT. WAVES 1 FT. A CHANCE OF SHOWERS..TUE...NW WINDS 15 TO 20 KT. WAVES 1 TO 2 FT..TUE NIGHT...NW WINDS 10 TO 15 KT. WAVES 1 FT..WED...W WINDS 10 TO 15 KT. WAVES 1 FT..THU...NW WINDS 5 TO 10 KT. WAVES 1 FT OR LESS. $$

18 Special Marine Warnings Issued for potentially hazardous over-water weather conditions of short duration (2 hours or less) and producing winds speeds or gusts 34 kt or greater not covered by existing longer fused products. Gusty showers/thunderstorms with winds 34 kt or greater Gusty showers/thunderstorms with winds 34 kt or greater Waterspouts Waterspouts

19 Special Marine Warnings BULLETIN - IMMEDIATE BROADCAST REQUESTED BULLETIN - IMMEDIATE BROADCAST REQUESTED SPECIAL MARINE WARNING NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 621 PM EST SUN NOV THE NATIONAL WEATHER SERVICE IN STERLING VIRGINIA HAS ISSUED A *SPECIAL MARINE WARNING FOR... CHESAPEAKE BAY NORTH OF POOLES ISLAND, MD... CHESAPEAKE BAY FROM POOLES ISLAND TO SANDY POINT, MD... * UNTIL 745 PM EST * AT 621 PM EST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A CLUSTER OF GUSTY SHOWERS ABOUT 20 MILES WEST OF BALTIMORE HARBOR.... MOVING EAST AT 45 MPH. IN ADDITION...GUSTY WINDS ASSOCIATED WITH A COLD FRONT WILL PASS OVER THE WATERS JUST AFTER THE SHOWERS PASS THROUGH AFTER 7 PM. *THIS ACTIVITY WILL AFFECT THE WATERS AFFECT... BALTIMORE INNER HARBOR... HART MILLER ISLAND... POOLES ISLAND... TOLCHESTER BEACH... MARINERS CAN EXPECT WIND GUSTS OVER 35 KT...HIGH WAVES...LIGHTNING AND HEAVY DOWNPOURS. BOATERS SHOULD SEEK SAFE HARBOR IMMEDIATELY UNTIL THIS STORM PASSES. LAT...LON $$

20 Marine Weather Statements Update/Continue Special Marine Warning Update/Continue Special Marine Warning Expire/Cancel Special Marine Warning Expire/Cancel Special Marine Warning Issued for long term sub-severe hazards lasting for longer than 2 hours that will impact marine operations Issued for long term sub-severe hazards lasting for longer than 2 hours that will impact marine operations

21 Marine Weather Statements MARINE WEATHER STATEMENT NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1045 AM EDT SUN AUG ANZ /O.CON.KLWX.MA.W T0000Z T1545Z/...A SPECIAL MARINE WARNING CONTINUES UNTIL 1145 AM EDT... FOR THE FOLLOWING AREA... CHESAPEAKE BAY FROM POOLES ISLAND TO SANDY POINT, MD AT 1044 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO INDICATE A LINE OF THUNDERSTORMS...PRODUCING STRONG WINDS OVER 35 KNOTS FROM CEDAR BEACH TO 9 MILES SOUTHWEST OF ROCK HALL...OR FROM 7 MILES WEST OF POOLES ISLAND TO 3 MILES NORTH OF SANDY POINT...MOVING NORTHEAST AT 15 MPH. OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO HART MILLER ISLAND...CARROLL ISLAND...TOLCHESTER BEACH AND ROCKY POINT. MARINERS CAN EXPECT GUSTY WINDS...HIGH WAVES...REDUCED VISIBILITIES...DANGEROUS LIGHTNING...AND HEAVY RAINS. BOATERS SHOULD SEEK SAFE HARBOR IMMEDIATELY...UNTIL THIS STORM PASSES. FREQUENT LIGHTNING IS OCCURRING WITH THIS STORM. IF CAUGHT ON THE OPEN WATER STAY BELOW DECK IF POSSIBLE...KEEP AWAY FROM UNGROUNDED METAL OBJECTS. $$

22 Nowcasts Issued for short term non-severe hazards but potentially dangerous conditions, such as with winds to 33 kt lasting for 2 hours or less. Issued for short term non-severe hazards but potentially dangerous conditions, such as with winds to 33 kt lasting for 2 hours or less. Sometimes combined with land zones, but oftentimes appearing only as a marine Nowcast. Sometimes combined with land zones, but oftentimes appearing only as a marine Nowcast.

23 Nowcasts SHORT TERM FORECAST NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 804 AM EDT FRI OCT ANZ530>537-DCZ001-MDZ005> > >018-VAZ > ANNE ARUNDEL MD-ARLINGTON/FALLS CHURCH/ALEXANDRIA VA-CALVERT MD-CARROLL MD-CHARLES MD-DISTRICT OF COLUMBIA DC-FAIRFAX VA-FAUQUIER VA-HARFORD MD-HOWARD MD-KING GEORGE VA-LOUDOUN VA-MONTGOMERY MD- NORTHERN BALTIMORE MD-PRINCE GEORGES MD-PRINCE WILLIAM/MANASSAS/MANASSAS PARK VA-SOUTHERN BALTIMORE MD-SPOTSYLVANIA VA-ST.MARYS MD-STAFFORD VA- CHESAPEAKE BAY FROM DRUM POINT, MD TO SMITH POINT, VA- CHESAPEAKE BAY FROM NORTH BEACH TO DRUM POINT, MD- CHESAPEAKE BAY FROM POOLES ISLAND TO SANDY POINT, MD- CHESAPEAKE BAY FROM SANDY POINT TO NORTH BEACH, MD- CHESAPEAKE BAY NORTH OF POOLES ISLAND, MD- TIDAL POTOMAC FROM COBB ISLAND, MD TO SMITH POINT, VA- TIDAL POTOMAC FROM INDIAN HEAD TO COBB ISLAND, MD- TIDAL POTOMAC FROM KEY BRIDGE TO INDIAN HEAD, MD- 804 AM EDT FRI OCT NOW......HEAVY RAIN AND THUNDERSTORMS AFFECTING THE MORNING COMMUTE......HEAVY RAIN AND THUNDERSTORMS AFFECTING THE MORNING COMMUTE... AT 804 AM EDT...DOPPLER RADAR INDICATED A LINE OF HEAVY RAIN WITH EMBEDDED THUNDERSTORMS...LOCATED FROM JUST WEST OF BALTIMORE TO JUST WEST OF WASHINGTON DC AND FURTHER TO THE SOUTH. THIS ACTIVITY WAS MOVING EAST AT 25 MPH. AT 804 AM EDT...DOPPLER RADAR INDICATED A LINE OF HEAVY RAIN WITH EMBEDDED THUNDERSTORMS...LOCATED FROM JUST WEST OF BALTIMORE TO JUST WEST OF WASHINGTON DC AND FURTHER TO THE SOUTH. THIS ACTIVITY WAS MOVING EAST AT 25 MPH. MORNING COMMUTERS SHOULD EXPECT TO ENCOUNTER BRIEF HEAVY RAIN...GUSTY WINDS UP TO 30 MPH...AS WELL AS LIGHTNING. SOME OTHER COMMUNITIES THAT WILL SEE THIS ACTIVITY THROUGH 930 AM INCLUDE LAUREL BROOK...SCARFF...BELLEVIEW...WOODBRIDGE...FALLSTON. THE TIDAL POTOMAC AND CHESAPEAKE BAY COASTAL WATERS WILL ALSO EXPERIENCE THIS ACTIVITY AFTER 830 AM. MARINERS SHOULD ANTICIPATE THE GUSTY WINDS AND REDUCED VISIBILITIES. $$

24 Marine Product Recap What’s Issued for the Waters?  Coastal Waters Forecast Issued four times daily (4 AM, 11 AM, 4 PM, 11 PM) 5 Day forecast 5 Day forecast Winds/Waves/Precipitation (Visibility)  NOWCAST Non-Routine, 2-3 hour duration Issued for sub-warning criteria weather: Issued for sub-warning criteria weather: Mainly precipitation trends  Marine Weather Statement Non-Routine, 2+ hours duration Update/Continue Special Marine Warning Update/Continue Special Marine Warning Expire/Cancel Special Marine Warning Expire/Cancel Special Marine Warning Issued for long term sub- severe hazards lasting for longer than 2 hours that will impact marine operations Issued for long term sub- severe hazards lasting for longer than 2 hours that will impact marine operations  Special Marine Warning Non-Routine, 2 hours or less Potentially hazardous weather Potentially hazardous weather Showers/thunderstorms with winds 34 kt or greater Showers/thunderstorms with winds 34 kt or greater Waterspouts, or large hail Sudden wind shift

25 NWS Homepage weather.gov/washington weather.gov/washington weather.gov/baltimore weather.gov/baltimore Hazards highlighted on front page Hazards highlighted on front page Use “point and click” to view forecasts and specific hazard information Use “point and click” to view forecasts and specific hazard information

26 Coastal Waters Forecast Coastal Waters Forecast Coastal Waters Forecast Headlines for long fused hazards listed at the top of the page Headlines for long fused hazards listed at the top of the page Headlines also highlighted at the top of Coastal Waters Forecast (Small Craft Advisory, Gale Warning, etc) Headlines also highlighted at the top of Coastal Waters Forecast (Small Craft Advisory, Gale Warning, etc)

27 Hazardous Weather Outlook

28 Alerts public to potential hazards and their impact Alerts public to potential hazards and their impact Potential hazards over the next 7 days Potential hazards over the next 7 days Marine hazards Marine hazards Coastal hazards Coastal hazards

29 Marine Weather Message

30 National Digital Forecast Database Graphical depiction of NWS forecast elements through 7 days Graphical depiction of NWS forecast elements through 7 days – Temperature – Weather – Sky Cover – Many more Program specific sectors Program specific sectors – Public – Marine – Tropical – Fire Weather Zoom capability to the WFO levelZoom capability to the WFO level

31 National Digital Forecast Database Zoomed into the Tidal Potomac and Chesapeake Bay Zoomed into the Tidal Potomac and Chesapeake Bay Marine specific elements highlighted Marine specific elements highlighted – Winds – Waves – Weather – Hazards

32 Hydrometeorological Prediction Center gov/ gov/ Current Weather Maps and Analyses Current Weather Maps and Analyses Surface Pressure Charts Surface Pressure Charts Forecast Maps of Surface Features Forecast Maps of Surface Features

33 Current Surface Map Isobars (lines of equal barometric pressure) Isobars (lines of equal barometric pressure) Low Pressure Low Pressure High Pressure High Pressure Fronts Fronts Troughs Troughs Updated every few hours Updated every few hours

34 Current Radar Accessible through HPC site as a larger regional loop OR Accessible through HPC site as a larger regional loop OR Local radar viewed at Baltimore/Washington site Local radar viewed at Baltimore/Washington site Detects rain, snow, thunderstorms Detects rain, snow, thunderstorms

35 Current Marine Observations National Data Buoy Center (NDBC) National Data Buoy Center (NDBC) Contains NOAA/NWS owned observation platforms Contains NOAA/NWS owned observation platforms

36 Current Marine Observations Chesapeake Bay Interpretive Buoy System (CBIBS) Chesapeake Bay Interpretive Buoy System (CBIBS) NOAA owned/funded NOAA owned/funded Includes buoys which are placed along the historic John Smith Trail Includes buoys which are placed along the historic John Smith Trail

37 Current Marine Observations NOAA Tides and Currents (includes PORTS) NOAA Tides and Currents (includes PORTS) noaa.gov/ noaa.gov/ More wind obs More wind obs Water level obs Water level obs Short term wind/water level forecasts Short term wind/water level forecasts

38 NOAA Tides and Currents PORTS – Physical Oceanographic Real Time System PORTS – Physical Oceanographic Real Time System Graph gives overview of past and current… Graph gives overview of past and current… – Water levels – Winds – Pressure – Temperature

39 NOAA Tides and Currents High resolution models High resolution models Forecast of winds (sustained) through 24 hours Forecast of winds (sustained) through 24 hours Forecast of water levels through 24 hours Forecast of water levels through 24 hours

40 WFO Baltimore-Washington forecasts significant wave heights in the local Coastal Waters Forecast (CWF) product. WFO Baltimore-Washington forecasts significant wave heights in the local Coastal Waters Forecast (CWF) product. Significant wave heights are the average heights (trough to crest) of the one-third highest waves. Significant wave heights are the average heights (trough to crest) of the one-third highest waves. For simplicity, significant wave heights are termed waves in the WFO Baltimore- Washington CWF. For simplicity, significant wave heights are termed waves in the WFO Baltimore- Washington CWF. Wind-Wave Correlations

41 NOAA Weather Radio (NWR) NOAA Weather Radio (NWR) – Tone Alarm (SMW) within a minute of issuance – All marine products are broadcast on NWR Marine Hazard Dissemination How Do We Convey the Message Today? Website (weather.gov/baltimore or weather.gov/washignton) Website (weather.gov/baltimore or weather.gov/washignton) – Colorful maps on website, click to see text – (http-wireless) Recorded Forecast (CWF only) Recorded Forecast (CWF only) – (703) (menu system) Third parties (USCG) retransmit Third parties (USCG) retransmit

42 Marine Safety Before going out onto the water…BE PREPARED!! Check the latest weather forecasts. Sources include: NOAA Weather Radio NOAA Weather Radio Television Media – The Weather Channel or Local TV Stations Television Media – The Weather Channel or Local TV Stations Internet, including our website at: Internet, including our website at:WEATHER.GOV/WASHINGTONWEATHER.GOV/BALTIMORE

43 Marine Safety While on the water…STAY ALERT!! Have a NOAA Weather Radio in your boat and continue to monitor the latest forecasts. Pay attention to changes in marine forecasts Pay attention to changes in marine forecasts Heed any issued advisories and warnings issued Heed any issued advisories and warnings issued React appropriately to observed changes of marine conditions React appropriately to observed changes of marine conditions

44 Marine Safety REMAIN ALERT for fast developing / approaching thunderstorms. Signs include: Dark, threatening clouds … increasing in number / growing vertically Dark, threatening clouds … increasing in number / growing vertically Steadily increasing winds / waves Steadily increasing winds / waves Flashes of lightning Flashes of lightning Heavy static heard on AM Radio Heavy static heard on AM Radio

45 Marine Safety When a thunderstorm approaches: Head for shore, if possible Head for shore, if possible While still in the boat, make sure to have on your personal flotation device and prepare for higher winds and waves While still in the boat, make sure to have on your personal flotation device and prepare for higher winds and waves When onshore, get out of the boat and seek shelter immediately When onshore, get out of the boat and seek shelter immediately

46 Waterspout – west of Crisfield, MD 3:30 PM EDT Sunday September 10, 2006

47 Waterspout characteristics: Short-lived ( usually <30 min.) Form from small showers or cumulus congestus) Move rapidly if associated with fast-moving shower 10- to 100-feet wide; move at 5 to 75 mph Visible funnel extends from a few 100 ft up to cloud base (~2000 ft over the Ches. Bay) Spin either clockwise or counter-clockwise Visible funnel forms from cooling of humid air due cooling/expansion (not by sucking the water!) Are called a tornado if it makes landfall Are difficult to detect by radar (little warning) Most common in late summer through the fall DO NOT GO NEAR THEM!!!!

48 Waterspout life cycle: 1. Dark spot: (light inner circle <100 ft dia. surrounded by a larger dark area of more diffuse shape/edges (no visible funnel) 2.Spiral pattern: alternating light/dark spiral bands (vortex growth) 3.Spray ring: swirling annulus of sea-spray (min winds ~50 mph) 4.Mature vortex: prominent visible funnel; full spiral pattern; max winds mph; funnel extends to cloud base 5.Decay: can occur abruptly when inflow air is cut off; displays maximum vertical tilt

49 BAD WEATHER ON THE BAY? Report your observations to the National Weather Service and help us to improve your Bay forecasts through reports of what is really happening. We are interested in winds and wave height estimates, current weather conditions, low visibilities in fog, and icing. Immediate reports have a direct impact on marine forecasts and warnings for you and your fellow mariners. However, even old reports are helpful as they can be reviewed to help improve future marine forecasts. Call our marine report hotline at or us at with your marine reports!

50 Marine Reporting System Report: Report: – Location (lat/lon) – Wind direction and speed – Wave height estimates – Weather and obstructions to visibility, if any

51 Part II Outline The Atmosphere The Atmosphere The Water Cycle The Water Cycle Weather Instrumentation Weather Instrumentation Weather Basics Weather Basics – Clouds – Fronts and air masses – Thunderstorms – Lightning – Hurricanes

52 Earth’s Atmosphere

53 Layers of the Atmosphere Temperature is used to define the layers of the atmosphere Temperature is used to define the layers of the atmosphere The Troposphere contains all of the weather! The Troposphere contains all of the weather!

54 Pressure “The exertion of force upon a surface by a fluid (e.g., the atmosphere) in contact with it.” Meteorologists use areas of higher or lower pressures to forecast the weather. Low pressure systems usually come with cold fronts. High pressure systems usually build behind the cold front, allowing pleasant weather for a day or two.

55 Measuring Pressure Barometer

56 Wind Air in motion relative to the earth's surface Air in motion relative to the earth's surface Air moves in 3 dimensions Air moves in 3 dimensions

57 Observing Wind Anemometer Wind sock Weather Vane Described with both distance and speed (mph)

58 Why does the Wind Blow? Pressure Gradient Force Force is due to differences in pressure. Tries to move air to eliminate pressure differences by causing air to flow from high pressure to low pressure

59 Why does the Wind Blow? 2.Coriolis Force Force is due to the earth's rotation. Causes moving objects (i.e. air, planes, birds, etc) to deflect to the right of their motion in the Northern Hemisphere

60 Why does the Wind Blow? 3.Friction The earth’s surface is rough Force that causes air to slow down and spiral into lows and out of highs.

61 Temperature A measure of the internal energy that a substance contains. This is the most measured quantity in the atmosphere.

62 Observing Temperature Thermometer Touch Degrees Fahrenheit (F) or Celsius (C)

63 Dewpoint Temperature Measure of the moisture content in the atmosphere Measure of the moisture content in the atmosphere High Dewpoint Temperature means there is high water vapor content  the air is moist or Humid High Dewpoint Temperature means there is high water vapor content  the air is moist or Humid

64 The Water Cycle The continuous movement of water between the earth and the atmosphere The continuous movement of water between the earth and the atmosphere Four Important Steps are… Four Important Steps are…

65 The Water Cycle Evaporation and Transpiration Evaporation  when a substance changes from the liquid phase to the gas phase Water  Water Vapor Transpiration  evaporation of water through plant membranes How water vapor, which is needed for clouds and precipitation, enters the atmosphere.

66 The Water Cycle Condensation Condensation  when a substance changes from the gas phase to the liquid phase Water Vapor  Water Condensation can be observed in the atmosphere as clouds, fog, dew, or frost form.

67 The Water Cycle 3. Precipitation Precipitation  water, either liquid or solid, that falls from the atmosphere to the surface. Clouds are composed of millions of water droplets that have condensed. These water droplets grow into larger droplets. Eventually, the droplets can grow large enough that they will not be able to stay suspended in the cloud. When this occurs, they fall out of the cloud as precipitation.

68 The Water Cycle 4. Ground Water and Runoff Groundwater  precipitation is absorbed into the ground Runoff  precipitation flow into streams when the ground cannot absorb any more water Some of the runoff will evaporate and some of the groundwater will be taken in by plants and then transpired.

69 Precipitation The process where water vapor condenses in the atmosphere to form water droplets that fall to the Earth as rain, sleet, snow, hail, etc. We want to measure what type and how much! The type depends on temperature.

70 Measuring Precipitation Measure LIQUID precipitation in a rain gage. For SOLID precipitation (snow or ice), measure with a ruler. You can also melt the snow or ice and pour it in a rain gage.

71 Weather Instruments Weather Instruments tell us what’s happening…especially for things we can’t see. We measure Wind, Precipitation, Temperature and Pressure. We use Radar, Satellites, and even Balloons!

72 Doppler Radar Tower is 100 feet tall! The 30 ft. wide white ball on top is where the radar dish is. Radar dish inside is 25 feet wide and spins constantly. It can see up to 250 miles away! Radar waves sent out hit a storm cloud. Some of the radar wave bounces off the cloud back to the radar. More waves are returned to the radar if the storm has hail or very heavy rain. It can even tell which way the wind is moving!

73 Satellites Satellites are sent high above the earth to take “pictures” of the clouds from above. This is a view that people usually don’t get to see. Satellites are sent high above the earth to take “pictures” of the clouds from above. This is a view that people usually don’t get to see.

74 Weather Balloons NWS Offices across the US release a weather balloon twice a day, once in the morning and again at night. The balloon has an Instrument packet that sends temperature, wind, and moisture data back to a computer.

75 Weather Balloons Data sent back from the Instrument Pack is plotted on a graph and sent to large computer processors in Maryland to create Numerical Weather Predictions Data sent back from the Instrument Pack is plotted on a graph and sent to large computer processors in Maryland to create Numerical Weather Predictions

76 Weather-Makers! The basics of Weather help forecasters know… What will happen next?

77 Forecasting the Weather In order to forecast the weather, meteorologists need to know “What’s going on?” We look at all of the parts of the weather (temperature, wind, pressure, precipitation). Then we look at what is causing the parts to behave like they do.

78 Fronts and Air Masses An air mass is a large body of air with generally uniform temperature and humidity. Fronts are the boundaries between two air masses. Fronts are classified as to which type of air mass (cold or warm) is replacing the other.

79 Clouds

80 Cloud Formation Clouds are made of water, either liquid or solid Clouds are made of water, either liquid or solid Clouds typically form when air rises. Clouds typically form when air rises. When air rises, the air's temperature cools and may reach its dewpoint temperature, at which point it becomes saturated. When air rises, the air's temperature cools and may reach its dewpoint temperature, at which point it becomes saturated. Once saturated, condensation occurs and the water vapor in the air will condense into tiny water droplets. Once saturated, condensation occurs and the water vapor in the air will condense into tiny water droplets. As millions of droplets form, a cloud will begin to take shape. As millions of droplets form, a cloud will begin to take shape.

81 How to Name that Cloud! Height (High, middle, low, or vertically developing) Height (High, middle, low, or vertically developing) Physical appearance Physical appearance Produce precipitation Produce precipitation

82 Naming of Clouds Latin roots Latin roots “cirro“  high, ‘curl of hair‘ “alto“  ‘middle‘ “stratus“  layer, sheet-like, low “cumulus“  heap-like, puffy “nimbus“  clouds producing precipitation Combinations can be made of the Latin roots Combinations can be made of the Latin roots

83 High Clouds Form above 20,000 feet (6000 meters) Form above 20,000 feet (6000 meters) Composed of ice crystals Composed of ice crystals Typically thin and white, but can be many different colors due to the angle of the sun Typically thin and white, but can be many different colors due to the angle of the sun Examples  Cirrus, Cirrostratus, Cirrocumulus

84 Mid-level Clouds Bases between 6,500 to 20,000 feet (2000 to 6000 meters) Bases between 6,500 to 20,000 feet (2000 to 6000 meters) Composed of either water droplets or ice crystals depending on time of year Composed of either water droplets or ice crystals depending on time of year Examples  Altostratus, Altocumulus

85 Low Clouds Bases below 6,500 feet (2000 meters) Bases below 6,500 feet (2000 meters) Mostly composed of water droplets Mostly composed of water droplets May contain some ice particles and snow if temperatures are cold enough May contain some ice particles and snow if temperatures are cold enough Example  Stratus, Stratocumulus, Nimbostratus

86 Vertically Developing Clouds Span the depth of the troposphere Span the depth of the troposphere Flat base; can grow to heights exceeding 39,000 feet (12,000 meters) Flat base; can grow to heights exceeding 39,000 feet (12,000 meters) They can contain both liquid droplets and ice particles. They can contain both liquid droplets and ice particles. Can become powerful thunderstorms Can become powerful thunderstorms Example  Cumulus, Cumulonimbus

87 Thunderstorms Needed Ingredients for a Thunderstorm: Moisture (1), Instability (2) and Lift (3) (1) (2) (3)

88 Thunderstorm Hazards Lightning Flash Floods Hail Tornadoes

89 Lightning One of the oldest observed natural phenomena on earth, but one of the least understood. A gigantic spark of static electricity Can be seen in volcanic eruptions, extremely intense forest fires, heavy snowstorms, large hurricanes. Most often seen in thunderstorms. Intra-cloud, Cloud-to- Ground, Cloud-to-Cloud, Cloud-to-Air

90 How Much Lightning? 2,000 thunderstorms at any moment Nearly 14.5 MILLION storms each year Lightning flashes about 40 times a second worldwide. Satellites help us see lightning around the world.

91 How Lightning is Created

92 Thunder A shock wave starts at each point along the path of the lightning bolt. Nearby lightning strikes produce thunder that is loud and short. As the shock wave moves away from the strike center, it stretches, diminishes, and becomes elongated. Then other shock waves from more distance locations arrive at the listener. At large distances from the center, the shock wave (thunder) can be many miles across. To the listener, the combination of shock waves gives thunder the continuous rumble we hear.

93 Tornadoes A tornado is a violently rotating column of air descending from a thunderstorm and in contact with the ground. Although tornadoes are usually brief, lasting only a few minutes, they can sometimes last for more than an hour and travel several miles causing considerable damage.

94 Hail Hail is precipitation that is formed when updrafts in thunderstorms carry raindrops upward into extremely cold areas of the atmosphere. Hail can damage aircraft, homes and cars, and can be deadly to livestock and people. One of the people killed during the March 28, 2000 tornado in Fort Worth was killed when struck by grapefruit-size hail. La Plata, MD inches diameter on April 28, 2002 Impact at speeds over 100 mph! Sign of a powerful storm.

95 Flash Floods Except for heat related fatalities, more deaths occur from flooding than any other hazard. Most flash floods are caused by slow moving thunderstorms, thunderstorms that move repeatedly over the same area or heavy rains from tropical storms and hurricanes. These floods can develop within minutes or hours.

96 Tropical Cyclones

97 Tropical Cyclone Basics Conditions that must be in place before a TC can form: a) Warm ocean waters (at least 80F) through a depth of about 150 feet. a) Warm ocean waters (at least 80F) through a depth of about 150 feet. b) An atmosphere which cools fast enough with height such that it is potentially unstable to moist convection. b) An atmosphere which cools fast enough with height such that it is potentially unstable to moist convection. c) Relatively moist air near the mid-levels of the atmosphere ( kft). c) Relatively moist air near the mid-levels of the atmosphere ( kft). d) Generally a minimum distance of 300 miles from the equator. d) Generally a minimum distance of 300 miles from the equator. e) A pre-existing near surface disturbance. e) A pre-existing near surface disturbance. f) Low values (<20 kt) of vertical wind shear between the surface and the upper troposphere. Wind shear is the change of wind speed/direction with height. f) Low values (<20 kt) of vertical wind shear between the surface and the upper troposphere. Wind shear is the change of wind speed/direction with height.

98 Tropical Cyclone Classification Stages Sustained wind speeds Tropical Depression Closed circulation (less than 39 MPH) Tropical Storm 39-73MPH Hurricane 74 MPH or higher

99 Saffir-Simpson Hurricane Scale (based on wind speed alone) Category Wind Speed (MPH) Damage Minimal Moderate Extensive Extreme 5>155Catastrophic

100 TC Structure

101 Hurricane Hazards Storm Surge Storm Surge High Winds High Winds Flooding Flooding Tornadoes Tornadoes Katrina, 2005 in Louisiana

102 Storm Surge Greatest potential for loss of life related to a hurricane is from a storm surge. Greatest potential for loss of life related to a hurricane is from a storm surge. Storm Surge= water that is pushed toward the shore by the force of the winds swirling around the storm. Storm Surge= water that is pushed toward the shore by the force of the winds swirling around the storm.

103 Generalizations of Storm Surge More intense storms cause higher surges. More intense storms cause higher surges. Highest surges occur usually to the right of the storm track. Highest surges occur usually to the right of the storm track. Fast moving storms = higher surges along the open coast. Fast moving storms = higher surges along the open coast. Slow moving storms=greater flooding inside bays and estuaries. Slow moving storms=greater flooding inside bays and estuaries.

104 Storm Surge

105 High Winds Satellites, reconnaissance aircraft, and land based radars are used to estimate the maximum surface wind speed in a hurricane. The intensity of a land- falling hurricane is expressed in terms of categories that relate wind speeds and potential damage. NHC uses the Saffir-Simpson Hurricane scale to classify hurricanes. Each time you go up a category, the damage goes up roughly by a factor of five. So, a category four hurricane will produce 25 times more damage than a category two hurricane. Satellites, reconnaissance aircraft, and land based radars are used to estimate the maximum surface wind speed in a hurricane. The intensity of a land- falling hurricane is expressed in terms of categories that relate wind speeds and potential damage. NHC uses the Saffir-Simpson Hurricane scale to classify hurricanes. Each time you go up a category, the damage goes up roughly by a factor of five. So, a category four hurricane will produce 25 times more damage than a category two hurricane.

106 High winds High rise buildings are also vulnerable to hurricane force winds, particularly at the higher levels since wind speeds tend to increase with height. Recent research suggests that winds increase one category as you go up 500 ft. High rise buildings are also vulnerable to hurricane force winds, particularly at the higher levels since wind speeds tend to increase with height. Recent research suggests that winds increase one category as you go up 500 ft. This is why is not uncommon for high rise buildings to suffer a great deal of damage due to windows being blown out. This is why is not uncommon for high rise buildings to suffer a great deal of damage due to windows being blown out.

107 High Winds Why do winds weaken as you go inland? Why do winds weaken as you go inland? They weaken due to friction caused by land and because hurricanes, once they move inland, lose their energy source which is the very warm waters of the ocean. They weaken due to friction caused by land and because hurricanes, once they move inland, lose their energy source which is the very warm waters of the ocean. A category four hurricane at landfall can weaken very rapidly to a category one in just six hours. This is because is a function of time and not distance, faster moving storms are going to push those winds inland more effectively than slower moving ones. A category four hurricane at landfall can weaken very rapidly to a category one in just six hours. This is because is a function of time and not distance, faster moving storms are going to push those winds inland more effectively than slower moving ones.

108 Damage done by Andrew 1992

109 Wind-blown debris can become deadly projectiles

110 Tornadoes Typically occur on the right side of the storm because of an influx of very warm moist air. Typically occur on the right side of the storm because of an influx of very warm moist air. As the hurricane is making landfall, winds at the surface begin to slow down due to friction, while winds a mile above the ground are still spinning very rapidly creating a favorable wind profile for tornadoes to form. As the hurricane is making landfall, winds at the surface begin to slow down due to friction, while winds a mile above the ground are still spinning very rapidly creating a favorable wind profile for tornadoes to form.

111 Tornadoes When associated with hurricanes, tornadoes are not usually accompanied by hail or a lot of lightning. When associated with hurricanes, tornadoes are not usually accompanied by hail or a lot of lightning. Tornado production can occur for days after landfall when the TC remnants maintain an identifiable low pressure circulation. Tornado production can occur for days after landfall when the TC remnants maintain an identifiable low pressure circulation. They can also develop at any time of the day or night during landfall. They can also develop at any time of the day or night during landfall. Classified using the Enhanced-Fujita Scale. Classified using the Enhanced-Fujita Scale.

112 Inland Flooding Intense rainfall is not directly related to the wind speed of tropical cyclones. Some of the greatest rainfall amounts occur from weaker storms that drift slowly or stall over an area. Intense rainfall is not directly related to the wind speed of tropical cyclones. Some of the greatest rainfall amounts occur from weaker storms that drift slowly or stall over an area. Inland flooding can be a major threat to communities hundreds of miles from the coast. Inland flooding can be a major threat to communities hundreds of miles from the coast. In a study from 1970 to 1999, freshwater flooding accounted for more than half (59%) of U.S. tropical cyclone deaths. In a study from 1970 to 1999, freshwater flooding accounted for more than half (59%) of U.S. tropical cyclone deaths.

113 Any Questions? NWS Baltimore/Washington Marine Program Leader Contact:


Download ppt "Marine Weather Course NOAA National Weather Service Baltimore/Washington Forecast Office."

Similar presentations


Ads by Google