[LeArc] Forecast Discussion : MLI@ 2/12/03 3:38:50 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 120947
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
345 AM CST WED FEB 12 2003

WHITE-OUT CONDITIONS, 60 MPH WINDS, THUNDERSNOW, AND A HIGH OF 43 
DEGREES- IT MUST BE GETTING TOWARDS SPRING...NO OTHER TIME OF YEAR 
WOULD WE GET SUCH A COMBINATION ALL IN ONE DAY.  LATEST SURFACE 
ANALYSIS INDICATING THAT THE COLD FRONT IS NOW WELL SOUTH AND EAST 
OF THE CWA...ALL THE WAY SOUTHERN ILLINOIS IN FACT.  AMAZING HOW FAR 
THESE SPRING TIME FRONTS CAN MOVE IN JUST 8 HOURS.  WINDS HAVE 
DIMINISHED TO 10 TO 15 MPH ACROSS CWA ATTM...THOUGH STILL SOME GUSTS 
TO NEAR 20 FAR EAST.  WIND CHILLS BECOMING A FACTOR...AND WITH TEMPS 
CONTINUING TO DROP IN THE CAA AND CLEAR SKIES...WE COULD BE 
APPROACHING ADVISORY CRITERIA BY SUNRISE.  WILL MONITOR THIS AS WE 
GET CLOSER TO ISSUANCE TIME.

MAIN FORECAST CONCERNS THIS MORNING INCLUDE TEMPS AND CLOUDS TODAY 
AND THURSDAY...AND THEN THE INCOMING SYSTEM FOR FRIDAY.

00Z MODELS APPEAR TO HAVE INITIALIZED RELATIVELY WELL...AND ARE IN 
GENERAL GOOD AGREEMENT THROUGH ABOUT 48 HOURS.  THERE ARE SOME 
PRETTY SIGNIFICANT DIFFERENCES AFTER THIS...MAINLY IN THE HANDLING 
OF A LOW PRESSURE SYSTEM THAT DEVELOPS OVER THE OK/NRN TX AREA BY 
FRIDAY AM...AT 60 HRS.  ETA IS VERY WEAK WITH THIS SYSTEM...AND 
KEEPS IT SIGNIFICANTLY FARTHER SOUTH THAN EITHER THE AVN OR 
UKMET...AND AFTER 60 HRS WEAKENS THE SYSTEM WHEN THE OTHERS 
STRENGHTEN IT THROUGH AT LEAST 72 HRS.  AVN IS SHOWING BEST 
CONTINUITY FROM PREVIOUS RUN ON DEVELOPMENT OF THE SURFACE LOW...SO 
HAVE GONE PRIMARILY WITH IT THIS FORECAST.

TEMPS TODAY SOMEWHAT TRICKY...WITH RIDGE DROPPING SOUTHEAST ACROSS 
THE AREA...FULL SUNSHINE...AND STILL STRONG WESTERLY WINDS.  WE SAW 
YESTERDAY WHAT FULL MID FEBRUARY SUNSHINE CAN DO...BUT WITH COLD AIR 
ADVECTION STILL OCCURRING AT SURFACE HAVE GONE SLIGHTLY WARMER THAN 
AVN MAV GUIDANCE...AND WITH A FAIRLY LARGE RANGE ACROSS CWA.

TONIGHT THERE COULD BE A BIG DROP WITH RIDGE STILL IN VICINITY...BUT 
WINDS STAY UP ENOUGH TO KEEP US FROM DROPPING OUT TO DEWPOINTS...AND 
HAVE GONE WITH COOLER MAV GUIDANCE FOR THIS TIME FRAME.  ALSO A FEW 
CLOUDS SNEAKING IN FROM THE NORTHWEST.

THURSDAY AND THURSDAY NIGHT...CLOUDS BEGIN COMING IN FROM THE 
SOUTHWEST AS THE WINDS TURN SOUTHERLY AHEAD OF THE NEW SYSTEM.  
WINDS NOT STRONG SO NO BIG WARM-UP...BUT ENOUGH TO REACH NEAR 40 
AGAIN IN THE SOUTH.  HOPE THE GP ENJOYS IT...BECAUSE IT APPEARS TO 
BE SHORT LIVED AS THE SOUTHWESTERN SYSTEM MOVES IN BY MIDNIGHT 
THURSDAY NIGHT.  HAVE KEPT PRETTY CLOSE TO THE AVN SOLUTION...EVEN 
TO PUTTING A NARROW BAND OF JUST SN ACROSS CENTRAL ZONES...AND A MIX 
SOUTH.  THIS IS ALL QUESTIONABLE ENOUGH THAT HAVE KEPT OUT THE ZR 
WORD FOR NOW.  SOMEWHAT DRY EASTERLY FLOW WILL HELP KEEP ANY ZR VERY 
SHORT LIVED.  FOR NOW HAVE LIMITED PRECIPITATION TO SOUTHERN TWO 
THIRDS OF THE CWA...WITH DRY NORTH.  FRIDAY MIXTURE OR RAIN AND SNOW 
CONTINUES TO AFFECT THE SOUTHERN TWO THIRDS.  TEMPS DO NOT QUITE 
SUPPORT MUCH RAIN...AND DRY NORTHEAST FLOW ALSO SUPPORTS MORE SNOW 
THAN RAIN OR MIXTURE...BUT HAVE DECIDED MENTIONED IT TO KEEP 
AWARENESS OF A WINTRY MIXTURE UP...AND TO KEEP OPTIONS OPEN.  

LITTLE OR NO CHANGES HAVE BEEN MADE TO THE GOING PACKAGE FROM FRIDAY 
NIGHT THROUGH TUESDAY.

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

$$

LRE