[LeArc] Forecast Discussion : MLI@ 2/17/03 3:23:12 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 172121
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
321 PM CST MON FEB 17 2003

REGION IS CAUGHT BETWEEN REMAINS OF STORM THAT BURIED ATLANTIC COAST 
AND APPALACHIANS OVER THE WEEKEND AND A VIRGOROUS LOW PRESSURE 
SYSTEM LIFTING NORTHEAST THROUGH THE EASTERN DAKOTAS.  STRATUS THAT 
BACKED ACROSS CWA EARLY THIS MORNING WAS STILL COVERING ABOUT THE 
EASTERN THREE FOURTHS OF THE CWA.  MID/HIGH CLOUD ASSOCIATED WITH 
NORTHERN PLAINS SYSTEM HAD SPREAD OVER MUCH OF IOWA BY MID 
AFTERNOON.  

MAIN CONCERN WILL BE THE CLOUD TRENDS OVERNIGHT AND THEIR IMPACT ON 
MIN TEMPS.  WEAK LOW LEVEL WINDS NEAR RIDGE AXIS ALONG MISSISSIPPI 
RIVER WILL HELP MAINTAIN STRATUS UNTIL SUNSET OVER AT LEAST THE 
EASTERN HALF OF THE CWA.  BY MID/LATE EVENING RIDGE WILL BE FAR 
ENOUGH EAST AND FLOW AHEAD OF NRN PLAINS LOW WILL BE STRONG ENOUGH 
TO SCOUR OUT THE LOW LEVEL MOISTURE.  MID/HIGH CLOUDS SHOULD PUSH 
EAST OF CWA PER AVN RH PROGS DURING THE EARLY MORNING HOURS.  A 
COMBINATION OF CLOUDS MOST OF NIGHT AND SOUTHWEST WINDS AND SOME WAA 
OVER NIGHT SHOULD KEEP TEMPS FROM FALLING TOO MUCH. COOLER MAV 
NUMBERS LOOK REASONABLE GIVEN CURRENT READINGS.  NEXT CONCERN WILL 
BE PRECIP CHANCES FOR TUESDAY NIGHT.  CURRENT FORECAST HAS LOW POPS 
ACROSS THE SOUTHERN CWA FOR WEDNESDAY/WEDNESDAY NIGHT. HOWEVER 
GFS/UKMET ARE SUGGESTING THREAT HAS SHIFTED TO TUESDAY 
NIGHT/WEDNESDAY MORNING.  MODELS DEVELOP WAVE ALONG COLD FRONT 
MOVING THROUGH MS VALLEY TUESDAY.  WAVE MOVES EAST THROUGH THE 
SOUTHERN PLAINS AS SHORTWAVE
ENERGY IN THE NORTHERN STREAM DROPS ACROSS IOWA TUESDAY NIGHT. 
NORHTERN STREAM ENERGY MAY BE ENOUGH TO HELP EXPAND PCPN SHIELD 
FURTHER NORTH.  WILL GO WITH LOW CHANCE POPS FOR -SN WITH AVN 
FORECAST SOUNDINGS KEEPING LOW LEVEL TEMPS JUST BELOW FREEZING.  
RIDGE PROGGED TO BUILD IN FOR WEDNESDAY...THEN SOUTHWESTERLY FLOW 
INCREASES BY THURSDAY AHEAD OF NEXT SYSTEM.

EXTENDED...
MODELS CONTINUE TO DEPICT ANOTHER STRONG STORM SYSTEM FOR LATE IN 
THE WEEK.  ECMWF/GFS ARE STRONGER AND FURTHER NORTH WITH THE 
SYSTEM AND SUGGEST ANOTHER SIGNIFICANT RAIN/SNOW EVENT FOR THE MID 
MISSISSSIPPI VALLEY.  THE UKMET ON THE OTHER HAND KEEPS SYSTEM 
FURTHER SOUTH.  FOR NOW WILL CONTINUE WITH CURRENT FORECAST UNTIL 
SOME MODEL CONTINUITY CAN BE ESTABLISHED.  ARTIC AIR RUSHES INTO 
REGION SUNDAY.  THEN GFS SUGGESTS MODERATING TEMPS AHEAD OF BROAD H5 
TROF MOVING INTO THE ROCKIES.  IF GFS IS RIGHT THEN SOME LIGHT PCPN 
WILL BE POSSIBLE MONDAY IN STRONG WAA.  

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

$$

DLF