FXUS63 KDVN 110921
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
321 AM CST FRI DEC 11 2009

.SYNOPSIS...
A BROAD TROUGH ACROSS THE UNITED STATES IS RESULTING IN NORTHWEST
UPPER LEVEL FLOW ACROSS THE MIDWEST.  SURFACE HIGH PRESSURE IN THE
MID SOUTH IS SLOWLY MOVING EAST ALLOWING SOUTHWESTERLY WINDS TO
DEVELOP IN THE CWA. WEST-SOUTHWEST FLOW AT 850MB OVER THE CENTRAL
PLAINS IS POISED TO BRING WARMER AIR TO OUR AREA TODAY AS THE OAX
850MB WAS 5C WARMER THAN US AT 00Z.

&&

.SHORT TERM...TODAY AND TONIGHT.
MAIN FORECAST ISSUE IN THE SHORT TERM WILL BE DEVELOPING WARM AIR
ADVECTION AND ITS IMPACT ON TEMPS AND CLOUDS. 

PATCHY SC-AC HAVE BEEN NOTED ALONG THE EDGE OF THE 500MB SHEAR
AXIS FROM IA NORTHWESTWARD. THUS PATCHY CLOUDS SHOULD DEVELOP AND
MOVE ACROSS THE AREA TODAY AS WAA STRENGTHENS. BUT THESE SHOULD
HAVE MINIMAL EFFECT ON MAX TEMPS WHICH WILL BE MORE CONSTRAINED BY
THE SNOW PACK. OVERNIGHT MINS WILL BE A CHALLENGE AS DOWNSTREAM
TEMPS VARY BY AS MUCH AS 15 DEGREES BASED ON WHETHER CLOUDS HAVE
DEVELOPED OR NOT. BUT WITH WAA IN PLACE...TONIGHT'S MINS SHOULD AT
LEAST BE WARMER THAN THIS MORNING...AND AGAIN IMPACTED TO SOME
DEGREE ESPECIALLY IN AREAS WITH THE DEEPER SNOW PACK. WOLF

.LONG TERM...SATURDAY THROUGH THURSDAY...
REGION WILL BE IN SPLIT FLOW THROUGH THE WEEKEND.  S/W ENERGY IS 
PROGGED TO UNDERCUT THE EASTERN PACIFIC RIDGE AND MOVE INTO THE SRN 
PLAINS. IN THE NORTHERN STREAM SEVERAL S/W/S DROP SOUTH ALONG THE 
BACK SIDE OF THE PACIFIC RIDGE...THEN SWINGS EAST ALONG THE U.S. 
CANADIAN BORDER. 

THE NORTHERN STREAM WAVE PUSHES A FRONT INTO THE CWFA BY SUNDAY 
AFTERNOON.  RETURN FLOW AHEAD OF THE FRONT AND BEHIND HIGH PRESSURE 
OVER THE SRN U.S. TRANSPORTS WARM/MOIST LOW LEVEL AIR INTO THE 
REGION SATURDAY AFTERNOON/NIGHT.  MODELS SHOW SOME ISENTROPIC LIFT 
WITH THE WAA SATURDAY EVENING...BUT CONDENSATION PRES DEFICITS 
SUGGEST MID LEVEL SATURATION OCCURS EAST OF THE MS RIVER.  SO KEPT 
CHANCE POPS GOING FOR SATURDAY NIGHT BUT KEPT THE HIGHEST NUMBERS 
EAST.  TEMP PROFILES SUGGEST A MIX OF ZR-/S- ESPECIALLY SOUTH. KEPT 
MENTION OF THE FZDZ/S- LATE SATURDAY NIGHT INTO SUNDAY WITH THE LIFT 
WANING...MID LEVELS DRYING OUT AND LOW LEVELS REMAINING SATURATED.  

SUNDAY NIGHT INTO MONDAY A SURFACE LOW SPINS UP OVER THE CENTRAL 
PLAINS AS SOME PHASING OCCURS BETWEEN THE NRN/SRN STREAMS.  THE 
SURFACE LOW IS PROGGED TO LIFT NE THROUGH IA BY MONDAY EVENING.  
MOISTURE APPEARS TO BE LACKING WITH THIS FEATURE SO KEPT POPS IN THE 
SLGT CHANCE CATEGORY.  CONTINUED WITH A MIX SUNDAY NIGHT AND WENT 
WITH SNOW MONDAY AS COLDER AIR MOVES IN.  

FOR MID WEEK HIGH PRESSURE BUILDS INTO WESTERN IA BY TUESDAY WITH H8 
TEMPS DROPPING WELL INTO THE TEENS BELOW 0C OVER THE REGION. THIS 
SHOULD RESULT IN DRY/COLD CONDITIONS.  TEMPS EXPECTED TO BE IN THE 
SINGLES DIGITS AGAIN BY WEDNESDAY MORNING WITH HIGHS IN THE TEENS TO 
MID 20S.  

THE REST OF THE FORECAST LOOKS ON TRACK AS HIGH PRESSURE MOVES SE 
AND WARMER AIR SURGES BACK INTO THE MID/UPPER MS VALLEY.  ...DLF...

&&

.AVIATION...
NOT MUCH OF CONCERN TO THE AVIATION COMMUNITY IN OUR AREA THIS
FORECAST PERIOD. DRY WEATHER AND VFR CONDITIONS ARE EXPECTED WITH
ONLY SOME PATCHY MID-LEVEL CLOUDS TODAY AND TONIGHT. WOLF

&&

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

$$

WOLF/DLF