[LeArc] Forecast Discussion : MLI@ 7/23/2003 2:00:40 PM

[learc@mailman.qth.net]

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


FXUS63 KDVN 231857
AFDMLI

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
155 PM CDT WED JUL 23 2003

.OVERVIEW...SEASONABLY ACTIVE PATTERN CONTINUES THIS SUMMER AS 60-90
KT JET REMAINS ENTRENCHED OVER CONUS WITH LONG WAVE TROUGH NEAR
MISSISSIPPI RIVER.  STRONG SURFACE HIGH RIDGE AXIS NOW INTO NW IA
MOVING SE AT 10-15 MPH.  UPPER PATTERN SHOWS CONTINUED VIGOROUS
PATTERN WITH HIGH SLIDING EAST NEXT 24-36 HOURS WITH NEXT MODERATE
STRENGTH TROUGH AND JET ENTERING BRITISH COLUMBIA TO AFFECT AREA LATE
FRIDAY INTO SATURDAY.  PERSISTENCE SHOWS AIRMASS OVER REGION WARMING
2-3 DEGREES PER DAY.

...TEMP TRENDS EARLY THEN CHANCE POPS WITH STORMS FRIDAY INTO
SATURDAY AND AGAIN INTO EARLY NEXT WEEK MAIN ISSUES...

.DIAGNOSIS (DAYS 1-3)...MODELS ALL HANDLING LARGER SCALE FEATURES AND
PLAN TO USE PERSISTENCE AND MODEL BLEND THROUGH THURSDAY NIGHT.  CALM
WINDS TONIGHT WITH CLEAR SKIES TO PRODUCE IDEAL RADIATIONAL COOLING
AND PERSISTENCE OVER RIDGE AXIS SUGGEST PATCHY FOG TOWARD DAYBREAK IN
FOG FAVORED LOW LYING AREAS...PLAN TO PUT IN FORECAST...LOWS A FEW
DEGREES BELOW GUIDANCE BLEND WITH NEAR RECORD OR RECORD LOWS (BRL/53,
CID/50, DBQ/51, MLI/54).  HIGH WITH RIDGE OVERHEAD AND LIMITED MIXING
WILL TEND NEAR LATEST BLEND WHICH IS BETTER THAN PAST FEW RUNS...OR
ABOUT 2-3 DEGREES WARMER THAN TODAY.  ALL MODEL SOLUTIONS THIS RUN
AND PAST 2 SUGGEST FAVORABLE THERMODYNAMIC CONDITIONS FOR CONVECTIVE
SYSTEM HIGH PLAINS LATE FRIDAY SLIDING INTO REGION...MAINLY NORTH OF
I-80 AHEAD OF NEXT FRONT.  WILL UP POPS TO 50 NORTH TIER AS STRONG
UPPER DIFFLUENCE AND LOW LEVEL JET AND MOISTURE AXIS VERY SUPPORTIVE
OF MIGRATION OF MATURE AND DECAYING STAGES OF SYSTEM AFTER MIDNIGHT.
BOUNDARY LAYER ENERGY POTENTIAL (BLEP)...WHICH HAS DONE VERY WELL ALL
SEASON AND ESPECIALLY PAST WEEK DETERMINING DAMAGING HIGH WINDS AND
TORNADIC POTENTIAL AND STRENGTH...SUGGESTS ONLY 40 KNOTS OR LESS DUE
TO UNFAVORABLE MOISTURE AND WINDSHEAR PROFILES CONCEPTUALLY ARE
REASONABLE. SATURDAY THOUGH MAY BE A DIFFERENT STORY...WITH FRONT
AROUND AND MOISTURE POOLING AND INCREASING INSTABILITY AND FORCING...
PASS THIS TO NIGHT FOLKS TO LOOK CLOSER AT.  PLAN TO STAY NEAR TO
SLIGHTLY ABOVE GUIDANCE FRIDAY/SATURDAY WITH DECENT WAA AND MOISTURE.

.EXTENDED (SUN-WED)...LONG WAVE TROUGH REMAINS OVER EASTERN 1/2 OF
CONUS WITH RIDGE AXIS SOUTH OF AREA SUGGEST FRONT TO REACH INTO SOUTH
SECTIONS OF AREA SATURDAY AND POSSIBLY INTO SUNDAY.  WITH 850 FRONT
MOVING BACK SUNDAY NIGHT WILL PUT POPS IN SOUTH SECTIONS AND NEXT
VIGOROUS SHORT WAVE OUT OF CENTRAL CANADA WARRANTS KEEPING POPS INTO
TUESDAY.  PROBABLY DECENT EVENT BUT POOR TIMING CONFIDENCE DUE TO
PHASING AND RESOLUTION CAPTURE ISSUES WITH MODELS.  WILL LEAVE
WEDNESDAY DRY FOR NOW.

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

$$

NICHOLS