[LeArc] Forecast Discussion : MLI@ 2/2/03 2:55:33 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 022101
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
255 PM CST SUN FEB 2 2003

WILL GET RIGHT TO IT...WITH BIG CHANGES NEEDING TO BE MADE IN NEAR TERM.

MODELS COMING INTO SOMEWHAT BETTER AGREEMENT ON SYSTEM MON-MON NGT.
12Z AVN/GFS STILL HANGING ONTO MORE DEVELOPMENT WITH
SOUTHERN STREAM SFC LOW...AND IS THE ODD MODEL OUT...BUT EVENTUALLY FALLS
INTO LINE WITH THE OTHER MODELS BY 00Z TUE. 12Z UKMET JUST IN AND
SUPPORTS MAIN SURFACE WAVE TRAVERSING SOUTHEAST IA MON MORNING BEFORE
LIFTING INTO GREAT LAKES WHILE DEEPENING RAPIDLY. THE BIG PROBLEM 
WITH THIS SYSTEM IS LACK OF DEEP MOISTURE WITH H85 ANALYSIS INDICATING
DRY PUNCH WITH PCPN CURRENTLY ARCING ALONG AND NORTH OF H85 AND 
H7 FRONTAL ZONES IN NORTHERN PLAINS AND UPPER MIDWEST. MOISTURE IS INCREASING
SOUTH WITH DEWPTS CLIMBING INTO L40S INTO NORTHERN/CENTRAL MO.
THIS SHOULD ADVECT NORTHWARD INTO FAR SOUTH FOR WHILE LATER TONIGHT AND
MON MORNING BEFORE GETTING SHUNTED EASTWARD WITH LOW PRESSURE. 
NOT MUCH IN WAY OF PCPN TONIGHT EXCEPT MAYBE SOME PATCHY DZ WITH THE 
FOG WHICH COULD BE DENSE IN SPOTS THOUGH GRADIENT INCREASING...SO NOT
CONFIDENT ON IT BEING WIDESPREAD. PCPN CHCS TONIGHT CONFINED TO 
THE NORTH AS H85 LOW TRACKS UP INTO EASTERN IA MON MORNING WITH H85
FRONT SAGGING SOUTHWARD. LOOKS LIKE ANY PCPN TONIGHT WILL BE 
RAIN...WITH RAIN THEN CHANGING TO SNOW FROM NORTHWEST TO SOUTHEAST ON MON
AS THE SURFACE LOW TRACKS NORTHEAST DRAGGING COLDER AIR IN ON STRENGTHENING
NORTHWEST WINDS. CHANGEOVER IN THE NORTHWEST ZONES SHOULD COME
BY LATE MORNING...THEN EARLY AFTERNOON ALONG THE MISS RIVER AND LATE PM
IN THE FAR S/E. AS FOR SNOW ACCUMS...H85 LOW TRACKS ACROSS EASTERN IA INTO
SOUTHERN WI WITH HEAVIEST SNOWS WEST OF THIS TRACK...SO NORTHWEST ZONES
FAVORED FOR HIGHEST AMOUNTS. STRONG DYNAMICAL SYSTEM SO ANTICIPATE 
HEALTHY DEFORMATION ZONE DESPITE LACK DEEP MOISTURE. QPF GENERALLY .10-.20 IN 
THE SNOW WITH RATIO/S FIGURED IN OF 8-15:1. MODEL TSECTS SHOW POTENTIAL
FOR DENDRITIC GROWTH AND THINK COULD SEE COUPLE HOURS WITH 
RATES APPROACHING 1 INCH OR SO...ESPECIALLY NORTHERN 1/3 - 1/2. SO WITH 
THIS IN MIND THINKING OF 2-4 IN THE NORTHWEST WITH 1-2 OR MAYBE 3 IN 
THE QUAD CITIES THEN TAPERING TO AROUND AN INCH OR SO FAR SOUTH AND EAST.
ONCE SYSTEM MOVES EAST DURING AFTERNOON AND EVENING...WIND MACHINE
EXPECTED TO KICK IN AND WOULDN/T BE SURPRISED TO SEE WINDS ABOVE ADVISORY
CRITERIA. THUS WITH FRESHLY FALLEN SNOW EXPECT SOME BLOWING/DRIFTING
AND LOW VISIBILITIES. DILEMMA IS WHAT TO DO WITH WINTER STORM WATCH WHICH
WAS POSTED FOR ENTIRE AREA. QUITE CONFIDENT WE WON/T SEE 6+ INCHES
OF SNOW. HOWEVER...A FEW INCHES OF SNOW AND WITH WINDS GUSTING 30-40 MPH
HATE TO REMOVE BECAUSE IT COULD BE TRICKY TRAVEL ESPECIALLY IN THE
NORTHWEST. SO...AFTER MUCH THOUGHT HAVE OPTED TO KEEP WATCH GOING FOR AREAS
NORTHWEST OF WASHINGTON TO DUBUQUE LINE AND WILL REMOVE ELSEWHERE
WITH ANTICIPATION THAT A WINTER WEATHER ADVISORY WILL BE NEEDED FOR SOME
PORTIONS ESPECIALLY THOSE IN THE REMAINING WATCH.

SYSTEM TO DEPART MON NGT WITH LINGERING FLURRIES INTO TUE MORNING AND
POSSIBLY LONGER IN DEEP CYCLONIC FLOW.

GAVE TEMPS MY BEST SHOT...BUT POTENTIAL FOR BIG BUST (AS EVIDENCE TODAY) IN
SUCH A CHANGEABLE PATTERN. 

NEXT SYSTEM WEDNESDAY WITH CHANCE OF SNOW...FOLLOWED BY REINFORCING 
SHOT OF ARCTIC CHILL. 

.EXTENDED (THU-SUN)...
TEMPERATURE FORECAST MAIN CONCERN AND WILL BE DEPENDENT ON HOW MUCH 
SNOW. COLD CANADIAN HIGH BUILDS IN TO END THE WEEK...THEN
SHIFTS EAST EARLY IN THE WEEKEND WITH RETURN FLOW AND SOME MODERATION
IN TEMPS. NEXT SYSTEM LATE SAT-SUN. 


.DVN...
IA...WINTER STORM WATCH MONDAY AND MONDAY NIGHT NEAR AND NORTHWEST OF A LINE
FROM WASHINGTON TO DUBUQUE. 
IL...NONE.
MO...NONE.

$$

05