Post by SKYSUMMIT on Apr 22, 2014 14:19:47 GMT -6
This may need a thread of its own very soon with the activity starting in the plains and then sliding east through time.
Jackson is already talking about severe weather in their 7 day package:
THE UPPER LEVEL PATTERN WILL REMAIN PROGRESSIVE HEADING INTO THE END
OF THE WEEK...AS A QUICK-MOVING UPPER TROUGH MOVES ACROSS THE PLAINS
STATES REPLACING THE UPPER RIDGE. SOUTHERLY LOW LEVEL FLOW WILL
RETURN BY THURSDAY MORNING...BRINGING A 1.3-1.4 INCH PWAT AIRMASS
BACK INTO THE DELTA BY THE AFTERNOON. CONTRARY TO THE GFS...THE
NAM/EURO/AND CANADIAN INDICATE A MORE ROBUST SHORTWAVE WITH THIS
SYSTEM...THUS WE OPTED TO GO ABOVE MAV POPS THURSDAY AFTERNOON/NIGHT.
THIS BRINGS RAIN CHANCES A BIT FARTHER SOUTH TO THE I-20 CORRIDOR.
MOST OF THE DAYTIME WOULD REMAIN DRY ON THURSDAY...WITH THUNDERSTORMS
DEVELOPING AHEAD OF THE ASSOCIATED SURFACE FRONT IN THE LATE
AFTERNOON...AND PUSHING EASTWARD THROUGH THE AREA. PROGGED 00Z
SBCAPES APPROACHING 2000 J/KG AND 0-6 KM BULK SHEAR VECTORS IN THE
40-50 KNOT RANGE OVER THE DELTA SUGGEST THE POTENTIAL FOR ORGANIZED
CONVECTION INCLUDING SOME SEVERE STORMS. THUS A LIMITED POTENTIAL FOR
SEVERE THUNDERSTORMS WILL BE INTRODUCED TO THE HWO/GRAPHICAST FOR
THIS TIME PERIOD FOR THE NORTHERN HALF OF THE AREA.
THE SURFACE FRONT WILL BECOME MORE DIFFUSE AND WILL ELONGATE FROM
WEST TO EAST DURING THE OVERNIGHT...LIKELY LIMITING THE SOUTHWARD
EXTENT OF PRECIPITATION THURSDAY NIGHT. /DL/
LONG TERM (FRIDAY THROUGH NEXT TUESDAY)...
/UPDATE/ THERE CONTINUES TO BE GROWING MODEL CONSENSUS IN A PERIOD
OF ACTIVE THUNDERSTORMS FROM SUNDAY PM THROUGH MONDAY AS A DEEP
NEGATIVELY-TILTED UPPER TROUGH BUILDS OVER THE MISSISSIPPI VALLEY.
CURRENT GUIDANCE INDICATES THE POTENTIAL FOR MULTIPLE ROUNDS OF
SEVERE WEATHER ACROSS THE REGION. GIVEN THE RUN-TO-RUN MODEL
CONSISTENCY SHOWING THIS SIGNAL...WE FELT IT WOULD BE PRUDENT TO
INTRODUCE MENTION OF SEVERE WEATHER POTENTIAL TO HWO/GRAPHICAST WITH
TODAYS FORECAST PACKAGE. IT GOES WITHOUT SAYING...THIS IS STILL IN
THE DAY 6/7 PERIOD AND THERE ARE STILL SEVERAL DETAILS WITH RESPECT
TO EXACT TIMING AND MODE THAT CANNOT BE RESOLVED AT THIS POINT IN
TIME. /DL/
THE FRONT WILL MOVE THROUGH TUESDAY WITH A LARGE UPPER LOW SPINNING
OVER THE OHIO VALLEY THROUGH THE END OF THE WEEK. THIS SHOULD BRING
IN MUCH COOLER AND DRIER AIR FOR THE BEGINNING OF MAY. /28/
Jackson is already talking about severe weather in their 7 day package:
THE UPPER LEVEL PATTERN WILL REMAIN PROGRESSIVE HEADING INTO THE END
OF THE WEEK...AS A QUICK-MOVING UPPER TROUGH MOVES ACROSS THE PLAINS
STATES REPLACING THE UPPER RIDGE. SOUTHERLY LOW LEVEL FLOW WILL
RETURN BY THURSDAY MORNING...BRINGING A 1.3-1.4 INCH PWAT AIRMASS
BACK INTO THE DELTA BY THE AFTERNOON. CONTRARY TO THE GFS...THE
NAM/EURO/AND CANADIAN INDICATE A MORE ROBUST SHORTWAVE WITH THIS
SYSTEM...THUS WE OPTED TO GO ABOVE MAV POPS THURSDAY AFTERNOON/NIGHT.
THIS BRINGS RAIN CHANCES A BIT FARTHER SOUTH TO THE I-20 CORRIDOR.
MOST OF THE DAYTIME WOULD REMAIN DRY ON THURSDAY...WITH THUNDERSTORMS
DEVELOPING AHEAD OF THE ASSOCIATED SURFACE FRONT IN THE LATE
AFTERNOON...AND PUSHING EASTWARD THROUGH THE AREA. PROGGED 00Z
SBCAPES APPROACHING 2000 J/KG AND 0-6 KM BULK SHEAR VECTORS IN THE
40-50 KNOT RANGE OVER THE DELTA SUGGEST THE POTENTIAL FOR ORGANIZED
CONVECTION INCLUDING SOME SEVERE STORMS. THUS A LIMITED POTENTIAL FOR
SEVERE THUNDERSTORMS WILL BE INTRODUCED TO THE HWO/GRAPHICAST FOR
THIS TIME PERIOD FOR THE NORTHERN HALF OF THE AREA.
THE SURFACE FRONT WILL BECOME MORE DIFFUSE AND WILL ELONGATE FROM
WEST TO EAST DURING THE OVERNIGHT...LIKELY LIMITING THE SOUTHWARD
EXTENT OF PRECIPITATION THURSDAY NIGHT. /DL/
LONG TERM (FRIDAY THROUGH NEXT TUESDAY)...
/UPDATE/ THERE CONTINUES TO BE GROWING MODEL CONSENSUS IN A PERIOD
OF ACTIVE THUNDERSTORMS FROM SUNDAY PM THROUGH MONDAY AS A DEEP
NEGATIVELY-TILTED UPPER TROUGH BUILDS OVER THE MISSISSIPPI VALLEY.
CURRENT GUIDANCE INDICATES THE POTENTIAL FOR MULTIPLE ROUNDS OF
SEVERE WEATHER ACROSS THE REGION. GIVEN THE RUN-TO-RUN MODEL
CONSISTENCY SHOWING THIS SIGNAL...WE FELT IT WOULD BE PRUDENT TO
INTRODUCE MENTION OF SEVERE WEATHER POTENTIAL TO HWO/GRAPHICAST WITH
TODAYS FORECAST PACKAGE. IT GOES WITHOUT SAYING...THIS IS STILL IN
THE DAY 6/7 PERIOD AND THERE ARE STILL SEVERAL DETAILS WITH RESPECT
TO EXACT TIMING AND MODE THAT CANNOT BE RESOLVED AT THIS POINT IN
TIME. /DL/
THE FRONT WILL MOVE THROUGH TUESDAY WITH A LARGE UPPER LOW SPINNING
OVER THE OHIO VALLEY THROUGH THE END OF THE WEEK. THIS SHOULD BRING
IN MUCH COOLER AND DRIER AIR FOR THE BEGINNING OF MAY. /28/
