[LeArc] Forecast Discussion : MLI@ 8/6/2003 4:44:45 AM

[learc@mailman.qth.net]

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


FXUS63 KDVN 060941
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
425 AM CDT WED AUG 6 2003

AREAL COVERAGE OF SHOWERS OVER THE EASTERN CWA AND JUST TO THE
SOUTH...HAS INCREASED OVERNIGHT AS VORT SEEN ON W/V IMAGERY RIGHT
OVER THE CWA HAVING ITS AFFECT. SHOWERS OVER THE EAST CENTRAL CWA
EVEN HAD A SPIRALING MOVEMENT UNDER THE VORT DURING THE PAST COUPLE
OF HOURS. STRATUS DECK ALSO GENERATED ON WEST FLANK OF VORT
GRADIENT OVER CENTRAL IA...BUT ENOUGH HOLES OVER THE NORTHWEST CWA
TO ALLOW FOR SOME FOG GENERATION THIS MORNING AND HAVE ACCOUNTED FOR
IN THAT ZONE GROUPING. ELSEWHERE FOG LIGHT ENOUGH OR NOT WIDESPREAD
TO BE REALLY OF ZONE MENTIONABLE THIS MORNING.

W/V IMAGERY ALSO SHOWING ANOTHER VORT OVER NORTHERN MN/NORTHWEST
ONTARIO...AND WITH UPPER VORTEX STILL HOLDING OVER THE EASTERN GRT
LKS...THIS FEATURE WILL LOOK TO GET SHUTTLED ON DOWN ACRS THE AREA
THIS AFTERNOON. FCST SOUNDINGS SUGGEST AIRMASS NOT REALLY TO CHANGE
MUCH FROM YESTERDAY...AND WILL BECOME INCREASINGLY UNSTABLE BY
THIS AFTERNOON. SHORT RANGE MODELS GENERALLY SUGGEST CAPES
APPROACHING THE 1K J/KG MARK AND LI'S TO -5...AND EXPECTED CVA
PUNCH INTO THAT SHOULD GENERATE SHOWERS AND A FEW THUNDERSTORMS. BUT
THOSE PARAMETERS ARE BASED ON TEMPS MAKING IT AT LEAST INTO THE LOWER
80S...AND WITH EXPECTED VARYING AMOUNTS OF CLOUD COVER TODAY THAT
MAY BE AT QUESTION. BUT STILL EXPECT UPPER 70S TO AROUND 80 EVEN
WITH CLOUD COVER...AND FCST CONVECTIVE TEMPS BY EARLY AFTERNOON ARE
GENERALLY TO BE AROUND 80. THUS 30 TO 40 POPS FOR TODAY STILL
WARRANTED. SOME PARTIAL CLEAR OUT LATER TONIGHT EXPECTED AS INCOMING
NVA SETTLES IN...POSSIBLY ALLOWING FOR SOME PATCHY FOG IN AREAS THAT
WILL GET SOME SHOWER ACTIVITY WITH NIL TO LITTLE NORTHERLY SFC WIND.

SHORT RANGE MODELS GENERALLY IN GOOD AGREEMENT IN TRYING TO LIFT CUT-
OFF UPPER LOW TOWARD THE SOUTHERN JAMES BAY REGION ON THU...WHILE
SHARP AND LARGE UPPER RIDGE EXTENDS ACRS THE PLAINS AND OVER THE
WESTERN PORTION OF HUDSON BAY. THIS EFFECTIVELY KEEPS DVN CWA IN
MERIDIONAL/STEEP NORTHERLY FLOW...WITH POTENTIAL OF ANOTHER
DISTURBANCE DOWN ACRS THE AREA AND AGAIN OVER A RELATIVELY UNSTABLE
AIRMASS. THIS IS WHERE MODELS DIVERGE ON EXTENT OF VORT ACTIVITY AND
POTENTIAL OF PRECIP GENERATION. NGM AND ETA/META DRY...WHILE GFS AND
UKMET BREAK-OUT SOME PRECIP AGAIN. AM DISTRUSTFUL OF STEEP NORTHERLY
CYCLONIC FLOW OVER SUCH AN AIRMASS(~80F OVER MID 60S DPTS) AND FEEL
UKMET ONTO SOMETHING...AND WILL INTRODUCE PRECIP CHANCE AT LEAST ACRS
THE EASTERN CWA FOR THU AFTERNOON.

NO CHANGES TO LONGER RANGE FOR NOW...


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

$$

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