[LeArc] Forecast Discussion : MLI@ 5/16/2003 1:59:27 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 161857
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
155 PM CDT FRI MAY 16 2003

.OVERVIEW...UPPER MIDWEST ENTRENCHED IN MILD NORTHEAST FLOW...HIGH
CLOUDS MAINLY SOUTH SECTIONS AND INTO MISSOURI FROM SLOW MOVING
CLOSED LOW PRESSURE SYSTEM IN SOUTHERN PLAINS.  SOME ENHANCED CUMULUS
FORMING FROM CHICAGO TO QUAD CITIES ALONG GREAT LAKES ENHANCED FLOW
BUT APPEARS SPRINKLES IF ANYTHING EXPECTED NEXT FEW HOURS WITH
DISSIPATION BY DUSK. UPPER AIR ANALYSIS SUPPORTS UPPER LOW TO
SOUTHEAST TO SLIDE EAST SOUTHEAST AND PRODUCE SOME HIGH CLOUDS NEXT
24 HOURS. IMPRESSIVE AMOUNT OF COLD AIR POOLING IN WESTERN CANADA
WITH -30 TO -35 C 5H TEMPS AND 100+ JET SUPPORTING MAJOR SYSTEM EARLY
NEXT WEEK.

...TEMPERATURES AND CLOUDS THIS WEEKEND NEAR TERM ISSUE WITH STRONG
SYSTEM LATE MONDAY INTO TUESDAY LONGER TERM CHALLENGE...

.DIAGNOSIS (DAYS 1-3)...MODERATE NORTHEAST FLOW EXPECTED THROUGH
SUNDAY MORNING...WILL USE PERSISTENCE FOR TEMPS SUGGESTING LOW SIDE
AGAIN TONIGHT AND HIGHS NEAR TO JUST BELOW FWC.  DECENT TEMPERATURE
GRADIENT TOMORROW OF AT LEAST 5+ DEGREES NORTHEAST 1/3 TO 1/2 AREA
WITH VARYING IMPACTS OF GREAT LAKES FLOW.  WILL OPT FOR LIMITED
CLOUDS SUNDAY FROM REMNANTS OF UPPER SOUTHERN PLAINS LOW AS SURFACE
WINDS COME BACK AROUND TO SOUTHEAST AND THUS CLOSER TO FWC/MET BLEND
MAV TOO COLD.  LOTS OF MOISTURE AND SOME CLOUDS AHEAD OF STRONG COLD
FRONT MONDAY KEEP LOWS ON HIGH SIDE. THEN MONDAY PM AND ESPECIALLY
EVENING VERY STRONG COLD FRONT PASSES WITH LINE OF STORMS AND SOME
SEVERE A NEAR CERTAINLY WITH LARGE HAIL AND DAMAGING WINDS.  TAKING
2500 CAPE AND TEMPS IN MID 80S WITH UPPER 60S DEWPOINTS...INITIAL
BLEP CALCULATIONS SUGGEST UP TO 72 KNOTS (OR ~83 MPH).  THUS...HAVE
UPDATED HWO TO MENTION SEVERE RISK LATE MONDAY.  BLEP CONTINUES TO
EXCEL IN GIVING PRE-EVENT WIND INTENSITIES OF STRAIGHT LINE WINDS AND
TORNADOES.  CALCULATIONS HAVE BEEN WITHIN 10% OF ESTIMATED HIGH
STRAIGHT LINE WINDS REPORTED WITH PAST TWO EVENTS AND ALSO WITHIN 10%
OF TORNADO INTENSITY STRENGTH OVER PAST 2 WEEKS.  BLEP SUGGESTS
ISOLATED TORNADOES POSSIBLE...ALL THIS BETTER ASSESSED IN 48 HOURS.

EXTENDED (TUE-FRI)...ALL SOLUTIONS SUPPORT AT LEAST BREEZY NW WINDS
TUESDAY AND MUCH COOLER.  WILL GO AT LEAST 2 CATEGORIES BELOW MEX AS
WILL BE LUCKY TO SEE MID TO UPPER 60S.  THEN...LOOKS QUIET WITH LARGE
QUESTION OF NEXT SYSTEM LATE THURSDAY AND FRIDAY...LEFT DRY FOR NOW
DUE TO LIMITED SIGNALS.  ON COOL SIDE WED/THU WITH LOWS POSSIBLY IN
30S WEDNESDAY AM FOR SOME FROST POTENTIAL.  LATER SHIFTS CAN EVALUATE
THIS AS GETS CLOSER.

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

$$

NICHOLS