[LeArc] Forecast Discussion : MLI@ 3/30/2003 2:04:11 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 300802
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
202 AM CST SUN MAR 30 2003

SURFACE WEATHER MAP SHOWED A COLD FRONT PUSHING SOUTHEAST ACROSS
THE LOWER PENINSULA OF MICHIGAN WITH HIGH PRESSURE BUILDING IN
BEHIND IT. THE HIGH WAS CENTERED OVER NEBRASKA. UPPER AIR CHARTS
SHOWED A NEGATIVELY TILTED TROF TO THE EAST OF AND CLOSE TO OUR
AREA. THE TROF AT 850 MB EXTENDED FROM WESTERN NEW YORK STATE INTO
SOUTHERN ALABAMA...AND THE 300 MB TROF EXTENDED FROM WESTERN LAKE
SUPERIOR INTO NORTHWEST TEXAS. HEIGHT FALLS WERE OCCURRING AHEAD OF
THIS TROF WHILE HEIGHT RISES WERE OCCURRING BEHIND IT. THE 300 MB
CHART SHOWED TWO AREAS OF HIGH WIND SPEEDS. ONE AREA WAS EAST OF THE
TROF WHILE THE SECOND AREA WAS DIVING OVER THE GREAT PLAINS FROM THE
SOUTHWESTERN-SOUTH CENTRAL CANADA AREA.

MODELS INITIALIZED WELL AND CONSISTENTLY AMONG THEMSELVES WITH
RESPECT TO UPPER AIR FEATURES.

FORECAST CHALLENGES INCLUDE WEATHER TODAY...WEATHER SYSTEM TO AFFECT
OUR AREA MONDAY NIGHT...AND THE WEATHER SYSTEM TO AFFECT OUR AREA ON
SATURDAY.


SHORT TERM (TODAY-TUE NIGHT)...

500 MB TROF LIFTS OFF TO THE EAST TODAY. CU WITH SNOW SHOWERS
OR SPRINKLES LIKELY AGAIN TODAY...WITH THE BEST CHANCES IN THE
AFTERNOON. MODELS INDICATE VORT MAX SWINGING SOUTHEAST ACROSS THE
AREA THIS AFTERNOON. ENOUGH COLD AIR LEFT BEHIND THE 500 MB TROF TO
LEAD TO STEEP LAPSE RATES FAVORABLE FOR CU DEVELOPMENT SIMILAR TO
WHAT WE HAD YESTERDAY. CU AND RELATED PRECIP WILL DIMINISH TOWARD
SUNSET AS WE LOSE THE SOURCE OF HEATING. A SURFACE SYSTEM THEN SWINGS
SOUTHEAST OUT OF THE SOUTHWESTERN-SOUTH CENTRAL CANADA AREA MONDAY
AND WILL BRING OUR NEXT CHANCE OF PRECIP. IT LOOKS LIKE THE BEST
CHANCES FOR RAIN WILL BE TOWARD THE NORTHEAST. SURFACE LOW TRACKS
NORTHEAST OF OUR AREA AND BRINGS A TROF THROUGH OUR AREA TOO. THE LOW
ALSO BRINGS A BOUNDARY SOUTH TOWARD OUR AREA BEHIND IT BUT THE
BOUNDARY DOESN/T EVER REACH OUR AREA. ANOTHER LOW FORMS ACROSS NORTH
DAKOTA MONDAY NIGHT ALONG THE BOUNDARY...THEN SLIDES SOUTHEAST. THAT
LOW THEN DISSIPATES AND ANOTHER LOW DEVELOPS ACROSS WYOMING AS THE
BOUNDARY BECOMES MORE EAST TO WEST ORIENTED FROM THE SOUTHERN GREAT
LAKES INTO SOUTHERN SOUTH DAKOTA.

GOING FORECAST IN THE SHORT TERM LOOKS GOOD SO DON/T ANTICIPATE ANY
CHANGES.


EXTENDED (WED-SAT)...

PERIOD BEGINS WITH AN EAST TO WEST FRONTAL BOUNDARY JUST TO THE
NORTH OF THE CWA. THE PRECIP SHOULD REMAIN NORTH OF IT OUT OF OUR
CWA. MODELS THEN HAVE DIFFERING SOLUTIONS ON HOW THE SYSTEM TO OUR
WEST AT THAT TIME DEVELOPS. MRF AND EUROPEAN MOVE A LOW RAPIDLY
ACROSS IOWA INTO MICHIGAN WITH A TRAILING COLD FRONT TO ITS
SOUTHWEST...WHILE THE UKMET KEEPS THE SURFACE LOW OVER THE GREAT
PLAINS WITH ANOTHER SURFACE LOW OVER SOUTHERN MICHIGAN. IF THE FIRST
SOLUTION MATERIALIZES...SHOWERS AND THUNDERSTORMS WOULD BE POSSIBLE
THURSDAY WITH NO PRECIP ON FRIDAY. IF THE SECOND SOLUTION
MATERIALIZES THEN SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE THURSDAY
AND FRIDAY. WILL GO WITH THE SECOND SOLUTION AS THIS ONE LOOKS THE
MORE LIKELY OF THE TWO. THIS IS ALSO THE SOLUTION USED IN THE GOING
FORECAST. ANOTHER SYSTEM THEN DEVELOPS OVER THE ROCKIES ON SATURDAY.
SHOWERS MAY AFFECT OUR AREA...WITH THE BEST CHANCES BEING ACROSS
SOUTHWESTERN PORTIONS OF THE AREA.

ASIDE FROM KNOCKING DOWN SOME WIND SPEEDS DURING THE EXTENDED PERIOD
OF THE FORECAST...GOING FORECAST IN THE LONG TERM HAS A GOOD HANDLE
SO DON/T ANTICIPATE ANY OTHER CHANGES AT THIS TIME.

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

$$

50


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