[LeArc] Forecast Discussion : MLI@ 3/31/2003 2:31:59 AM

[learc@mailman.qth.net]

The following weather message is provided by McDonough County E.S.D.A.


FXUS63 KDVN 310829
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
223 AM CST MON MAR 31 2003

SURFACE WEATHER MAP SHOWS A TROF WORKING ITS WAY THROUGH OUR CWA...
HEADING SOUTHEAST. A WARM FRONT WAS APPROACHING OUR AREA FROM THE
GREAT PLAINS. SATELLITE SHOWS SOME ALTOCUMULUS EXTENDING EASTWARD
FROM THE LEADING EDGE OF THIS WARM FRONT. AT 08Z THIS ALTOCUMULUS
WAS AS FAR EAST AS AN ALGONA TO OTTUMWA LINE. RADAR SHOWS SOME
FLURRIES IN EXTREME EASTERN PARTS OF THE CWA. A VORT MAX HELPED SET
THESE FLURRIES OFF EARLIER IN THE NIGHT. AROUND 04Z THEY WERE
FALLING FROM NEAR DUBUQUE TO MOUNT CARROLL. UPPER AIR CHARTS SHOW A
DEPARTING TROF TO OUR EAST. MAX WIND SPEEDS AT 300 MB ASSOCIATED
WITH THAT TROF HAVE ROUNDED THE BASE OF IT SO THE TROF SHOULD
CONTINUE MOVING EAST. 850 MB CHART SHOWED AN ADVANCING WARM FRONT
OVER THE GREAT PLAINS. IT EXTENDED FROM CENTRAL NORTH DAKOTA INTO
CENTRAL KANSAS. 500 MB CHART SHOWED HEIGHT RISES OVER CENTRAL THIRD
OF THE COUNTRY...WITH HEIGHT FALLS OVER SOUTHWESTERN CANADA. HEIGHT
FALLS WERE OCCURRING OVER THE EASTERN THIRD OF THE COUNTRY IN
ASSOCIATION WITH THE DEPARTING TROF.

MODELS INITIALIZED WELL WITH RESPECT TO UPPER AIR FEATURES...WITH
THE AVN INITIALIZING THE BEST.

FORECAST CHALLENGES INCLUDE EXTENT AND INTENSITY OF RAIN TODAY...A
POSSIBLE BACKDOOR COLD FRONT TO AFFECT OUR AREA TUESDAY INTO
WEDNESDAY...AND POSSIBLE SEVERE WEATHER ON THURSDAY.


SHORT TERM (TODAY-WEDNESDAY)...

MODELS BRING THE WARM FRONT TO OUR WEST EASTWARD DURING THE DAY. AVN
IS THE ONLY MODEL WHICH INDICATES PRECIP OVER OUR AREA...AND ONLY IN
THE NORTHEAST PORTIONS. BEST CHANCES FOR PRECIP WILL BE OVER
NORTHEAST PORTIONS OF OUR AREA...BUT PRECIP WILL BE POSSIBLE OVER
NEARLY ALL BUT THE SOUTHERN TWO-THIRDS OF OUR AREA. GOING FORECAST
HAS SPRINKLES OR LIGHT RAIN WORDING...WILL REMOVE SPRINKLES WORDING
AND GO ONLY WITH LIGHT RAIN. SYSTEM THEN MOVES EAST OF OUR AREA
TONIGHT WITH A COLD FRONT MOVING SOUTH TOWARD OUR AREA BEHIND IT.
WINDS WILL BECOME SOUTHWESTERLY ON TUESDAY BEFORE IT NEARS OUR AREA
HOWEVER...ALLOWING FOR A BIG WARMUP. 70S ARE LIKELY OVER MUCH OF
OUR AREA WITH SOME SOUTHWESTERN SECTIONS POSSIBLY SEEING LOWER 80S.
WARM TEMPERATURES WILL CONTINUE INTO WEDNESDAY BUT WILL LIKELY BE
COOLER THAN THOSE IN TUESDAY AS MORE CLOUDS WILL BE AROUND. AM NOT
SURE HOW FAR SOUTH THE BACKDOOR COLD FRONT WILL DROP ON TUESDAY INTO
WEDNESDAY BEFORE IT RETURNS NORTH. AVN/UKMET/ECMWF KEEP IT NORTH OF
OUR AREA...WITH THE ETA/MESO ETA BRINGING IT FURTHER SOUTH INTO OUR
AREA. WILL GO WITH PRESENT THINKING TO KEEP THE FRONT NORTH OF OUR
AREA AND WILL LET LATER SHIFTS DECIDE ON HOW FAR SOUTH IT/LL GO. IF
IT DOES GO SOUTH INTO OUR AREA...IT WILL DRAMATICALLY AFFECT
WEDNESDAY/S HIGHS IN THOSE AREAS NORTH OF IT. SOUTH AND SOUTHWEST
WINDS THEN INCREASE OVER OUR AREA WEDNESDAY NIGHT IN RESPONSE TO A
DEVELOPING STORM SYSTEM TO OUR WEST.


EXTENDED (THURSDAY-SUNDAY)...

MODELS HAVE DIFFERING SOLUTIONS ON THE STORM SYSTEM TO AFFECT OUR
AREA THURSDAY INTO FRIDAY. MRF LIFTS THE SURFACE LOW NORTHEAST FASTER
THAN THE UKMET/ECMWF DUE TO RELATIVELY STRONG SHORTWAVE AT 500 MB
LIFTING NORTHEAST. WILL GO WITH UKMET/ECMWF BLEND AS THEY LOOK MORE
REASONABLE. SURFACE LOW TRACKS NORTH OF OUR AREA THURSDAY. SHOWERS
AND THUNDERSTORMS ARE POSSIBLE THURSDAY. ALTHOUGH SEVERE
THUNDERSTORMS ARE POSSIBLE THURSDAY PER THE GOING HAZARDOUS WEATHER
OUTLOOK...I DON/T SEE ANY OBVIOUS SIGNS OF SEVERE WEATHER THAT DAY.
FOR CONTINUITY/S SAKE THOUGH...WILL CONTINUE WORDING OF POSSIBLE
SEVERE THUNDERSTORMS IN THIS MORNING/S HAZARDOUS WEATHER OUTLOOK. MRF
IS THEN SLOWER AND STRONGER THAN THE UKMET/ECMWF LATER IN THE WEEK
WITH THE NEXT STORM SYSTEM TO DEVELOP OVER THE ROCKIES. GIVEN THE
TENDENCY OF THE MRF TO GO TOO FAST...THEN PERHAPS TOO SLOW...WILL GO
WITH THE MORE MIDDLE OF THE ROAD UKMET/ECMWF.

.DVN...
IA...NONE.
IL...NONE.
MO...NONE.

$$

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