FXUS63 KDVN 292028
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
225 PM CST SUN NOV 29 2009

.SYNOPSIS...
ANALYSIS SHOWS POST FRONTAL MVFR CLOUDS OVER MOST OF THE FORECAST
AREA WITH CLEARING TO MOVE IN BASED ON AWIPS DISTANCE-TIME FEATURE
BY MID TO LATE EVENING.  SURFACE RIDGE AND MODEST UPPER AIR RIDING
ALSO SUPPORTS CLEARING SKIES AND LIGHT WEST WINDS BY DAY BREAK.
UPSTREAM MIN TEMPS IN SURFACE RIDGE THIS AM AND CURRENT DEWPOINTS
SUGGEST LOWS TO BE 2 TO 4 DEGREES BELOW GUIDANCE. CLOSED UPPER LOW
OVER WEST TEXAS TO MOVE SLOWLY EAST AND NORTHEAST INTO OHIO VALLEY
AND POSE IN SIGNIFICANT IMPACT TO REGION AS SURFACE HIGH REMAINS OVER
UPPER MIDWEST NEXT SEVERAL DAYS.   ..NICHOLS..

&&

.SHORT TERM...TONIGHT AND MONDAY...
TONIGHT...SUBSIDENCE SUPPORTS SKIES TO CLEAR BY MIDNIGHT OVER ALL OF
FORECAST AREA.  THEN USING LOCAL STUDIES AND TECHNIQUES...INDICATES
MINS OF MID TO UPPER 20S REASONABLE TONIGHT.  PERSISTENCE PER EARLIER
COMMENTS ALSO SUPPORTS GOING THIS FAR BELOW GUIDANCE.

MONDAY...MOSTLY SUNNY WITH MODERATE WEST WINDS OF 5 - 15 MPH TO ALLOW
FOR MAX TEMPS TO RISE A FEW DEGREES ABOVE NORMAL INTO MID TO UPPER 40S.
OVERALL...DECENT WEATHER FOR LATE NOVEMBER.   ..NICHOLS..

.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY...
SHORTWAVE IN THE NORTHERN STREAM PASSES NORTH OF THE AREA MONDAY
NIGHT KEEPING THE AREA QUIET. RETURN FLOW ON THE BACK SIDE OF THE
SFC HIGH TUESDAY WILL ALLOW AN IMPRESSIVE WARM UP WITH WELL ABOVE
NORMAL TEMPERATURES FOR EARLY DECEMBER ALONG WITH QUIET WX
CONTINUING THROUGH TUESDAY NIGHT.

WEDNESDAY...DPROG/DT OF THE MODELS INDICATES PHASING OF THE NORTHERN
AND SOUTHERN STREAMS WILL OCCUR AFTER THE SOUTHERN STREAM SYSTEM IS
EAST OF THE AREA. THEREFORE...DRY CONDITIONS ARE NOW EXPECTED.
TEMPERATURES SHOULD BE AROUND OR SLIGHTLY ABOVE NORMAL.

WEDNESDAY NIGHT THROUGH SATURDAY IS QUITE INTERESTING. UPPER LOW IN
THE NORTHERN STREAM SLOWLY ROTATES THROUGH THE AREA WITH H85
TEMPERATURES DROPPING INTO THE NEGATIVE DOUBLE DIGITS. THIS COLD
POCKET COMBINED WITH STRONG CYCLONIC FLOW AND SEVERAL VORT MAXES
ROTATING THROUGH THE AREA WILL RESULT IN PLENTY OF CLOUDS AND AT
LEAST FLURRIES IF NOT SHSN. SO...HAVE LOWERED MAX TEMPS DURING THIS
PERIOD EVEN FURTHER. MODELS ARE SLOWER WITH THE UPPER LOW MOVEMENT
THAN YESTERDAY SO THE BELOW NORMAL TEMPERATURES SHOULD LINGER INTO
SATURDAY.

QUIET WX SHOULD BE SEEN ON SUNDAY AS SFC HIGH PRESSURE MOVES EAST OF
THE AREA. THE BENEFIT OF SOME SUN SHOULD ALLOW TEMPERATURES TO
MODERATE TO JUST BELOW NORMAL.

ANOTHER STRONG UPPER LEVEL SYSTEM DIVES INTO BRITISH COLUMBIA NEXT
WEEKEND WITH SOME VERY COLD AIR FROM ALASKA. THIS SYSTEM WILL INDUCE
LEE CYCLOGENESIS IN ALBERTA PROVIDENCE. THE GEM/GFS INDUCE SAID
CYCLOGENESIS THURSDAY NIGHT/FRIDAY WHILE THE UKMET/ECMWF INDUCE
CYCLOGENESIS FRIDAY NIGHT/SATURDAY. WHAT HAPPENS AFTER THAT IS
UNKNOWN AS THE ECMWF AND GFS DIVERGE INTO TWO COMPLETELY DIFFERENT
WX REGIMES. THIS DIVERGENCE IS TRACEABLE TO INDIVIDUAL MODEL PHYSICS
AND HOW EACH MODEL TRIES TO PHASE ENERGY FROM THE NORTHERN AND
SOUTHERN STREAMS.   ..08..

&&

.AVIATION...
BKN-OVC CLOUDS WITH BASES 1-3K AGL TO DISSIPATE OVER ALL TERMINALS
BETWEEN 00 AND 06Z...OTHERWISE VSBYS AOA 7 MILES.  THEN...VFR
CONDITIONS AND FAIR SKIES REST OF THE PERIOD WITH LIGHT WESTERLY
WINDS.  ..NICHOLS..

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.

&&

$$

NICHOLS/08