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235
FXUS63 KDVN 232028
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
328 PM CDT TUE SEP 23 2014

.SYNOPSIS...
ISSUED AT 327 PM CDT TUE SEP 23 2014

12Z UA ANALYSIS HAD AN UPPER HIGH OVER THE WESTERN GREAT LAKES. A
LLJ RAN FROM WEST TEXAS INTO THE CENTRAL PLAINS AND A PLUME OF
TROPICAL MOISTURE RAN FROM MEXICO INTO THE NORTHERN PLAINS.
SATELLITE TRENDS THROUGH MID AFTERNOON SHOW A SLOW INCREASE IN HIGH
AND SOME MID LEVEL CLOUDS ACROSS IOWA THAT SLOWLY EVAPORATE AS IT
HITS THE DRY AIR OVER THE GREAT LAKES.

18Z SFC ANALYSIS HAS WEAK LOWS IN WESTERN SOUTH DAKOTA WITH HIGH
PRESSURE OVER THE OHIO VALLEY. DEW POINTS WERE IN THE 40S OVER THE
OHIO VALLEY WITH 50S OVER PARTS OF THE GREAT LAKES AND PLAINS.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 327 PM CDT TUE SEP 23 2014

DRY CONDITIONS WILL BE SEEN FROM LATE THIS AFTERNOON THROUGH SUNSET
WITH ONLY A SLOW INCREASE IN CLOUDS.

AFTER SUNSET...VERY WEAK FORCING BEGINS MOVING INTO THE FAR WEST
ASSOCIATED WITH AN APPROACHING UPPER LEVEL DISTURBANCE. THIS FORCING
WEAKENS WITH TIME THROUGH SUNRISE. THUS AN INCREASE IN CLOUDS WILL
BE SEEN THROUGH SUNRISE WEDNESDAY. AT THE VERY WORST SOME ISOLATED
SPRINKLES MAY OCCUR ACROSS THE NORTHWEST QUARTER OF THE AREA.

THE FIRST ROUND OF WEAK FORCING EXITS THE AREA BY MID DAY WEDNESDAY.
THUS ANY SPRINKLES ACROSS THE NORTHWEST THIRD OF THE AREA WILL
SLOWLY END.

ANOTHER ROUND OF WEAK FORCING ARRIVES MID TO LATE WEDNESDAY AFTERNOON.
THE DRYNESS OF THE AIR SHOULD RESULT IN NOTHING MORE THAN ISOLATED
SPRINKLES OVER THE WESTERN THIRD OF THE AREA.


.LONG TERM...(WEDNESDAY NIGHT THROUGH NEXT TUESDAY)
ISSUED AT 327 PM CDT TUE SEP 23 2014

WEDNESDAY NIGHT THROUGH FRIDAY...WEAKENING UPPER WAVE STILL ON TRACK
TO DRIFT EASTWARD ACRS THE CWA WED NIGHT INTO THU. ALTHOUGH THIS
FEATURE STILL TRIES TO TOP-DOWN SATURATE AS IT PROGRESSES
ACRS...EXTENT OF DRY LOW TO MID LEVELS JUST TO ALLOW FOR SOME
ISOLATED TO SCTRD HIGH BASED SPRINKLES WED NIGHT INTO THU MORNING
ACRS MAINLY THE NORTHERN TWO THIRDS OR HALF. MAIN EFFECT OF THE
UPPER LEVEL WAVE PROBABLY STILL TO BE A PASSING MID DECK OF CLOUDS
WED NIGHT INTO THU MORNING...BEFORE THE WAVE PASSES AND WASHES OUT
TO ALLOW FOR EVEN THIS DECK TO DECAY AS THU PROGRESSES. MAY TURN
MOSTLY SUNNY BY THU AFTERNOON ESPECIALLY WEST OF THE MS RVR. CLOUD
COVER MAY ALLOW FOR SOME LOWS WED NIGHT NOT TO DIP OUT OF THE MID
50S...COOLER EAST OF THE MS RVR WHERE THERE WILL BE SOME TIME BEFORE
CLOUDS THICKEN AND ADVECT ACRS...IF LINGERING RIDGE AXIS OFF TO THE
EAST DOESN/T EAT AT THEM AS THEY TRY TO MOVE THAT WAY. SOME SUNSHINE
BY THU AFTERNOON TO ALLOW FOR ADVERTISED WARM UP TO TAKE HOLD WITH
VALUES IN THE MID TO UPPER 70S. THERMAL PROFILES CONTINUE TO
MODERATE INTO FRI WITH THE LOW TO MID LEVEL THERMAL STRUCTURE
SUPPORTING WIDESPREAD UPPER 70S TO LOWER 80S...ALTHOUGH A
MIXING-LIMITING H85 MB INVERSION AND BOUNDARY LAYER SOUTHEASTERLY
FLOW MAY INHIBIT THE TRUE WARM UP POTENTIAL SOME. LARGE DIURNAL
SWINGS FROM LOWS TO HIGHS TO CONTINUE IN DRYING SFC LAYER AND WHEN
CLOUD COVER IS NOT A FACTOR.

SATURDAY THROUGH NEXT TUESDAY...12Z RUN MEDIUM RANGE SOLUTIONS
GENERALLY SUGGEST BROAD REX TYPE BLOCK TO REIGN ACRS MUCH OF THE
CONUS OVER THE WEEKEND. REMNANT UPPER LOW MAY GYRATE SOMEWHERE ACRS
THE REGION ROM MO AND ACRS IA...BUT DRY VERTICAL COLUMN AND DOMINANT
RIDGE ACRS THE MID CONUS TO LIMIT ANY KIND OF MOISTURE RETURN FLOW TO
FUEL ANY PRECIP. WILL KEEP THE FCST DRY INTO MONDAY WITH NEAR OR
ABOVE NORMAL TEMPS ESPECIALLY DURING THE DAY. IN-BUILDING L/W TROF
FROM THE WEST TO EVENTUALLY TRANSLATE INTO THE NEXT MAIN PRECIP
CHANCES BY NEXT TUE OR WED AS IT DRAWS GULF MOISTURE AND EVEN A
POSSIBLE WAVE UP THE MS RVR VALLEY TO THE LEE OF IT. THE MEDIUM RANGE
MODEL SOLUTIONS AGAIN DIVERGE ON TIMING...PHASING AND HANDLING OF
THIS PROCESS...AND PROBABLY WILL CONTINUE TO THROUGH THE NEXT 24-48
HOURS OF RUNS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1219 PM CDT TUE SEP 23 2014

VFR CONDITIONS ARE EXPECTED THROUGH 00Z/25 AS HIGH PRESSURE MOVES
TO THE EAST COAST. A PASSING UPPER LEVEL DISTURBANCE WILL INCREASE
MID AND HIGH CLOUDS THAT MAY RESULT IN SOME SPRINKLES ACROSS
EASTERN IOWA AFT 03Z/24.

&&

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

$$

SYNOPSIS...08
SHORT TERM...08
LONG TERM...12
AVIATION...08







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