[LeArc] Forecast Discussion : MLI@ 9/30/02 3:13:08 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 302021
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
320 PM CDT MON SEP 30 2002

STRONG SWLY FLOW CONTINUES TO PUMP MORE SUMMERLIKE TEMPERATURES INTO
THE REGION TODAY.  TEMPS NEAR 90 ACROSS SOUTHERN HALF OF CWA WITH MID
80S NORTH. STRONG FLOW OCCURRING AHEAD OF SURFACE TROUGH FROM LOW OVER
NW MN THROUGH NW IA AND KS.  MAIN COLD FRONT STILL WELL TO THE NW OVER
SOUTH DAKOTA. S/W MOVING NE THROUGH NRN PLAINS THIS AFTERNOON ALONG WITH
SURFACE TROUGH HELPING TO GENERATE NARROW LINE OF TSRA FRM JUST NE OF
DSM INTO SERN MN.  U/A PATTERN STILL SHOWS BROAD SWLY FLOW BETWEEN
RIDGE OVER SERN U.S. AND TROUGH OVER THE PACIFIC COAST.

NO MAJOR DIFFERENCES NOTED IN MODEL INITIALIZATION THIS MORNING.
AVN/ETA HAVE COME INTO CLOSER AGREEMENT MOVING  COLD FRONT OUT OF THE
NORTHERN PLAINS AND THROUGH THE MISSISSIPPI VALLEY WEDNESDAY.  MOST
NOTABLE DIFFERENCE IS THE ETA IS PUSHING FRONT FURTHER SOUTH INTO
MISSOURI WEDNESDAY WHILE AVN HOLDS THE FRONT OVER CENTRAL/NORTHERN
MISSOURI. SWLY FLOW ALOFT WOULD SUGGEST THAT AVN IS THE WAY TO GO.

MOST IMMEDIATE CONCERN IS CONVECTION DEVELOPING OVER CENTRAL IA ATM.
ENE MOVEMENT OF TSRA FORCES A MENTION OF SCT TSRA IN NW SECTION THIS
EVENING.  LATER TONIGHT MODELS CONTINUE TO SUGGEST PCPN
DEVELOPING/MOVING INTO SOUTHERN SECTIONS.  MOST LIKELY A RESULT OF
ELEVATED CONVECTION EXPECTED TO DEVELOP IN GOOD WAA PATTERN OVER NRN
KS.  IF CONVECTION FIRES...IT SHOULD MOVE NE TOWARD CWA...HOWEVER
TIMING SUGGESTS ANY PCPN WILL HOLD UNIL THE VERY LATE TONIGHT OR EARLY
TUESDAY.  WILL LEAVE OUT MENTION FOR TONIGHT AND KEEP ALL POPS IN THE
SECOND PERIOD.  WK SURFACE TROF LAYS OUT E/W ACROSS CWA TUESDAY.  WITH
APPROACHING SPEED MAX PER SPC DISCUSSION AND UNSEASONABLY WARM AIR
OVER SOUTHERN CWA...WILL CONTINUE MENTION THUNDER MOST AREAS.  MAIN
PCPN EVENT STARTS TUESDAY NIGHT AND EXTENDS INTO THURSDAY WITH COLD
FRONT SAGGING SOUTH THROUGH REGION.  LIKELY POPS ARE WARRANTED TUESDAY
NIGHT MOST AREAS THEN HIGHER POPS SHIFT SOUTH WEDNESDAY AND THURSDAY.
NORTHERN SECTIONS SHOULD BE OUT OF THE RAIN THREAT AFTER WEDNESDAY
MORNING AS FRONT PUSHES INTO MISSOURI.


LOWS TONIGHT WILL REMAIN MILD WITH DEW POINTS IN THE LOW 60S IN STRONG
SOUTHERLY WIND CONTINUING.  WILL GO WITH WARMER MET NUMBERS IN THE
SOUTH SINCE WAA MID CLOUDS ARE EXPECTED LATE TONIGHT.  TEMPS IN THE
NORTH SHOULD BE CLOSE TO THE MAV VALUES WITH GENERALLY CLEAR SKIES
AFTER THIS EVENING.  TUESDAY TEMPS WILL ONCE AGAIN BE ABOVE NORMAL.
HOWEVER...WITH MORE CLOUDS AND 850 TEMPS SLIGHTLY COOLER THAN TODAY...
DON'T EXPECT TEMPS AS HIGH AS TODAY AND WILL GO A COUPLE OF DEGREES
COOLER.  AFTER TUESDAY MOS NUMBERS ARE IN DECENT AGREEMENT AND SEE NO
REASON TO DIFFER.



EXTENDED (FRIDAY THROUGH MONDAY)
LONG RANGE MODELS IN GOOD AGREEMENT...LIFTING SUBSTANTIAL PIECE OF
ENERGY OUT OF SW U.S. TROF.  MRF/AVN SHOWS NEGATIVELY TILTED TROF/SFC
LOW LIFTING FROM KS INTO WI FRIDAY.  TRACK AND TIMING OF SYSTEM FAVOR AN
ACTIVE WEATHER DAY FOR THE REGION.  THERE IS SOME QUESTION THOUGH AS
TO THE IMPACTS OF LILLI ON THIS SYSTEM.  LASTS NIGHTS MRF A LITTLE
FURTHER W THAN 29/00Z RUN AND PLACES REMANANTS OF LILLI OVER MO BOOTHEEL
BY FRI MORNING.  BEYOND FRIDAY MODELS DISAGREE ON ENERGY MOVING THROUGH
WRN PACIFIC RIDGE.  MRF MOVES ENERGY ACROSS SRN CANADA WHILE...AT THE
SAME TIME...EJECTS SW U.S. TROF ACROSS SOUTHERN U.S. ECMWF AND TO SOME
EXTENT THE CANADIAN MODEL SUGGEST THE SW U.S. TROF WILL REMAIN IN PLACE
AND STRENGTHEN AS WRN PACIFIC  SYSTEM DROPS INTO TROF.  DUE TO THE
UNCERTAINTY WILL NOT MAKE ANY DRASTIC CHANGES TO THE GOING FORECAST FOR
SATURDAY THROUGH MONDAY.  ALTHOUGH BOTH SOLUTIONS SUGGEST THAT TEMPS MAY
NOT BE AS COOL AS PREVIOUSLY THOUGHT.


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

DLF