Presentation on theme: "…SPRING FORECAST 2011…. …SPRING FORECAST 2011…. WEAKENING La Nina? WEAKENING La Nina? MAJOR DROUGHT FOR LOWER PLAINS and DEEP SOUTH PLANTING DELAYS CONCERNS...AGAIN..."— Presentation transcript:
…SPRING FORECAST 2011…. …SPRING FORECAST 2011…. WEAKENING La Nina? WEAKENING La Nina? MAJOR DROUGHT FOR LOWER PLAINS and DEEP SOUTH PLANTING DELAYS CONCERNS...AGAIN... 7TH TIME IN 8 YEARS PLANTING DELAYS CONCERNS...AGAIN... 7TH TIME IN 8 YEARS MUCH ABOVE NORMAL SEVERE WX SEASON MUCH ABOVE NORMAL SEVERE WX SEASON
...REVIEW OF WINTER … WHAT HAPPENED TO ALLL THOSE THE MILD WINTER FORECASTS ???
Wxrisk WINTER FORECAST
MUCH BELOW NORMAL TEMPS OVER SE...OHIO VALLEY... AND GENERALLY BELOW NORMAL E OF THE ROCKIES SUPER DRY OVER LOWER PLAINS INTO THE DELTA … SUPER WEST OVER CALIF...GREAT BASIN AND UPEPR PLAINS
BELOW NORMAL TEMPS E OF THE ROCKIES... SMALL AREAS OF BELOW NORMAL OVER UPER PLAINS & SE STATES MUCH BELOW NORMAL RAINFALL SW INTO LOWER PLAINS… MIDWEST & E COAST: BUT ONLY WET AREAS IN CONUS OVER UPEPR PLAINS
COLD SWITCHES LOWER PLAINS AND EASTERN. MIDWST WARMS UP? PLAINS/ MIDWEST DEEP SOUTH VERY DRY WHY??
SUPER DRY OVER LOWER PLAINS TRHOUGH ALL DEEP SOUTH AND VA.... AND SUPER WET...AGAIN...OVER UPPER PLAINS
WHY WAS DEC SO COLD? The development of extremely large and intense GREENLAND BLOCK (call a -NAO in the wx biz) in the Jet stream... along with a huge RIDGE over central North Pacific … which caused a HUGE west coast ridge to develop and set up the very cold persistent pattern. This pattern was NOT typical moderate/ strong LA NINA winter pattern we see over North America
Not much changed in the pattern. There was still large and intense GREENLAND BLOCK (call a -NAO in the wx biz) in the Jet stream... along with the strong a RIDGE western North America which made for a cold stormy pattern for Upper Plains/ Midwest / northeast US-- again NOT typical JAN pattern with a moderate/ strong LA NINA over North America WHY WAS JAN SO COLD?
WHY was DEC-JAN so cold & stormy FEB was NOT? AO turned STRONGLY negative around NOV at times SEVERELY negative... much like WINTER and held through all of DEC and JAN... then collapsed late in JAN... Turning strongly POSITIVE after FEB 2
WHY was DEC-JAN so cold & stormy FEB was NOT? Like the AO … the NAO also turned Negative around NOV Moderate to strongly Negative... much like WINTER and held through all of DEC and JAN...then collapsed late in JAN... Turning MODERATELY POSITIVE after FEB 2
FEB 2011 … THINGS CHANGD.... Jet stream map from FEB 2 MIDWEST BLIZZARD FEB 18 Jet stream map NOTE the Trough is now over the Plains... and we have Ridge over the se states – OPPOSITE of what we saw in DEC- JAN BLUE AREA over West coast= Trough.. NOT a Ridge … and RED are over Deep South is a Ridge … back in DEC / Jan that was a trough
Lets look at SOIL MOISTURE... WHY? Soil moisture is the most overlooked aspect of seasonal forecasting... large areas of saturated and drought regions can and DO influence the pattern
The 2/15/11 Drought map shows the largest & deepest drought for Mid FEB since 2000
Areas SOUTH of the DASHED LINE show DROUGHT areas and increasing trend for MORE dryness VERY WET AREAS OVER LAST FEW MONTHS and weeks
The LARGE areas of SUPER WET regions in close proximity of large areas of Super DRY will lock in Mean storm track for most of the SPRING and enhance Velocities in both Polar and Subtropical jet stream.... enhancing severe wx threats for Midwest
LA NINA Does it stay strong or is it weakening ? LA NINA into the Summer..or does it dissipate completely ?
LA NINA DEC 2010
LA NINA JAN 2011 The pool of sub-surface COLD water is what was strng... so the La Nina stayed strong EL NINO and LA NINA events are “fed” from the SUB SURFACE waters rising to the surface.
WEAKENING LA NINA IN THE SPRING 2011 By FEB the LA NINA is weakening at a steady pace… compare this map to the Jan 2011 map
WEAKENING LA NINA IN THE SPRING 2011 FEB 2 the large DARK BLUE area just below the surface was deep and large … 20 days later it is MUCH weaker... FEB 2 SUB SURFACE FEB 22 SUB SURFACE
WEAKENING LA NINA IN THE SPRING 2011 These graphs are from the ASSUIEs wx folks.. best in the world at tracking ENSO events... You can clearly see the recent bounce / WARMING of the La Nina event
FORECASTING LA NINA into the SPRING / SUMMER 2011 European model forecasts from the Key ENSO region 3.4. from the last 2 months... are in very strong agreement of steadily weakening La Nina through the Spring THEN holding as WEAK La Nina into the Summer 2011 JAN FEB 15
LA NINA MATCHES FOR THIS SPRING ARE: BUT NOT 1988
QT weather already talking “ DROUGHT LIKE 1988” hype
CFS model forecasts for the Key ENSO region 3.4. is in very strong agreement with EURO of steadily weakening La Nina through the Spring...THEN holding as WEAK La Nina into the Summer 2011 FORECASTING LA NINA into the SPRING / SUMMER 2011
IRI climate center charts over 20 various ENSO models : TREND is whats important. TREND is weakening La Nina..stays weak into Summer
PDO IS CLEARLY IN THE VERY COLD WATER PHASE or “NEGATIVE” -PDO means trough on West coast & RIDGE over SE states. For Upper Plains & Midwest this makes for very active storm track & weather pattern but for Lower Plains / Deep South More dryness
MODELS CAN SEE INTO MID MARCH … AND THE DATA SUPPORTS THE MARCH FORECAST Persistent West coast trough and se US ridge... so Lows track into Central/ Upper Plains then into Midwest... bypassing lower Plains / Delta
SUMMARY SUMMARY ANOTHER TOUGH SPRING… ANOTHER TOUGH SPRING… A ny “summer” forecasts issued in March/ early April LIKELY to be wrong A ny “summer” forecasts issued in March/ early April LIKELY to be wrong LA NINA is weakening BUT CURRENT data keeps 'WEAK” La Nina into Past June into Summer LA NINA is weakening BUT CURRENT data keeps 'WEAK” La Nina into Past June into Summer Lower Plains & Deep South DROUGHT WILL GET WORSE Lower Plains & Deep South DROUGHT WILL GET WORSE Best areas will be ECB / TN VALLEY Best areas will be ECB / TN VALLEY If the LA NINA holds on into JULY then DROUGHT could expand into WCB and Lower ECB If the LA NINA holds on into JULY then DROUGHT could expand into WCB and Lower ECB Very active SEVERE WX season... Below Normal activities over Gulf coast states after MAY 1 Very active SEVERE WX season... Below Normal activities over Gulf coast states after MAY 1
OVERSEAS SPRING FORECASTS COMES OUT NEXT WEEK OVERSEAS SPRING FORECASTS COMES OUT NEXT WEEK CHINA will likely have WEATHER problems… so will UKRAINE / Western and RUSSIA and K-STAN S AMERICA & AUSTRALIA LOOK BETTER S AMERICA & AUSTRALIA LOOK BETTER
column over at Agweb.com column over at Agweb.com SUMMER FORECAST Preliminary IDEAS APRIL 20 SUMMER FORECAST Preliminary IDEAS APRIL 20 FINAL MAY 15 FINAL MAY 15