Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 272018
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
318 PM CDT MON OCT 27 2014

.SYNOPSIS...
ISSUED AT 317 PM CDT MON OCT 27 2014

SURFACE LOW AT 18Z WAS CENTERED OVER NORTHEAST IOWA WITH A WARM
FRONT REACHING EAST INTO LOWER MI AND COLD FRONT TRAILING SOUTHWEST
THROUGH CENTRAL IA INTO NW MO. EASTERN IOWA...NORTHWEST ILLINOIS
AND NORTHEAST MISSOURI RESIDED IN THE BREEZY...WARM CAPPED WARM
SECTOR...WITH EARLY AFTERNOON TEMPERATURES IN THE MID AND UPPER
70S AND DEWPOINTS IN THE UPPER 50S. IN THE UPPER LEVELS...A
DEEPENING UPPER LOW WAS OVER NORTH DAKOTA WITH A BROAD AREA OF
DIVERGENCE AND LIFT OUT AHEAD ACROSS THE DAKOTAS INTO MN PRODUCING
A LARGE SWATH OF LIGHT RAIN IN THAT REGION. FURTHER SOUTH...A FEW
WEAK SHORTWAVE RIPPLES WERE EMBEDDED IN THE SOUTHWEST FLOW ALONG
WITH AN 80 KT UPPER LEVEL JET LIFTING OUT FROM THE SW U.S. AT 850
MB...12Z ANALYSIS SHOWED A SWATH OF MOISTURE AT THAT LEVEL OVER
EASTERN IA INTO THE WESTERN GREAT LAKES...DISCONNECTED FROM
RETURNING GULF MOISTURE OVER MEXICO AND TX BY VERY DRY SOUNDINGS
OVER OK...AR AND KS.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 317 PM CDT MON OCT 27 2014

INITIAL FOCUS IS ON THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS AS
THE COLD FRONT ADVANCES THROUGH THE REGION TONIGHT. BREEZY...AND MUCH
COOLER WEATHER THEN FOLLOWS FOR TUESDAY.

SHORT TERM MODELS...BACKED BY THE LOCATION OF SURFACE PRESSURE FALLS
OVER NORTHERN LOWER MI...DEPICT THE NORTHEAST IA SURFACE LOW
ADVANCING E-NE...DRAGGING THE SURFACE COLD FRONT THROUGH THE
FORECAST AREA ROUGHLY BETWEEN 7 PM AND MIDNIGHT. WHILE THE BEST
MID LEVEL FORCING WILL BE MAINLY WELL NORTH OF THE AREA...THERE
WILL BE MODEST MID LEVEL SUPPORT TO INTERACT WITH GULF MOISTURE
PROGGED TO REACH INTO NORTHERN IL LATE TONIGHT TO PRODUCE
WIDESPREAD SHOWERS. SUFFICIENTLY STEEP MID LEVEL LAPSE RATES WILL
SUPPORT AT LEAST A FEW THUNDERSTORMS IN THE EVENING. GREATEST
POPS...IN THE HIGH CHANCE TO LOW END LIKELY CATEGORY...ARE KEPT
FOR MAINLY EAST OF THE MS RIVER WHERE THESE CONDITIONS BEST COME
TOGETHER THIS EVENING. FURTHER WEST...COVERAGE WILL BE MORE
ISOLATED TO SCATTERED OVER EASTERN IA AND NE MO ALONG THE
ADVANCING FRONT FROM LATE THIS AFTERNOON AND EARLY EVENING. BASED
ON THE PROGRESSIVE NATURE AND LIMITED MOISTURE...QPF AMOUNTS WERE
KEPT WELL BELOW A TENTH ON AN INCH WITH LOCAL QUARTER INCH AMOUNTS
STILL POSSIBLE WITH ANY HEAVIER SHOWERS IN IL THIS EVENING. COLD
AIR ADVECTION THAT FOLLOWS OVERNIGHT WILL DRAW DOWN THE COOL
AIRMASS OVER THE NORTHERN PLAINS...WITH SHORT TERM HIGH RES MODELS
APPEARING TO HAVE A GOOD HANDLE SHOWING MIN TEMPERATURES AROUND
SUNRISE IN THE LOWER 40S NORTH TO NEAR 50 IN THE SOUTH AND EAST.

TUESDAY...A MUCH COOLER...DRIER AIRMASS SURGES INTO THE REGION WITH
850 MB TEMPERATURES CRASHING FROM THE TEENS CELSIUS OVER THE AREA
THIS AFTERNOON...TO NEAR OR BELOW ZERO BY TUESDAY EVENING. THE TIGHT
CYCLONIC PRESSURE GRADIENT AROUND THE OCCLUDING CYCLONE OVER THE
UPPER GREAT LAKES WILL KEEP SURFACE WINDS PRIMARILY WESTERLY WITH
GUSTS OF 25 TO 30 MPH LIKELY IN THE AFTERNOON. MODELS MAINTAIN A
SUGGESTION OF A WRAP AROUND MOISTURE AND STRATOCU DECK REACHING
INTO AT LEAST THE NORTHERN THIRD OF THE FORECAST AREA BY AFTERNOON
TO WARRANT PARTLY TO MOSTLY CLOUDY WORDING THERE. DEEP MIXING INTO
THE COLD ADVECTION FLOW WILL BE NEEDED FOR HIGHS TO REACH
ADVERTISED MID 50S NORTH TO LOWER 60S SOUTHEAST.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 317 PM CDT MON OCT 27 2014

DRY AND COOL CONDITIONS WILL BE SEEN ACROSS THE AREA TUESDAY NIGHT
AND WEDNESDAY AS CANADIAN HIGH PRESSURE MOVES THROUGH THE AREA.
TEMPERATURES SHOULD AVERAGE NEAR OR A BIT BELOW NORMAL.

WEDNESDAY NIGHT/THURSDAY A WEAK DISTURBANCE MOVES THROUGH THE AREA
FROM THE PLAINS. MOISTURE IS VERY LIMITED AND THE OVERALL FORCING IS
QUITE WEAK. SOME SPRINKLES OR ISOLATED SHOWERS MAY OR MAY NOT BE
POSSIBLE DURING THE PASSAGE OF THE DISTURBANCE. IF SPRINKLES OR
ISOLATED SHOWERS WOULD OCCUR...IT WOULD BE VERY LATE WEDNESDAY NIGHT
INTO THURSDAY MORNING.

THURSDAY NIGHT ON...
THE MODEL CONSENSUS HAS DRY AND COLD CONDITIONS THURSDAY NIGHT
THROUGH SATURDAY AS CANADIAN HIGH PRESSURE MOVES THROUGH THE
MIDWEST. TEMPERATURES WILL AVERAGE WELL BELOW NORMAL.

THE SIGNAL IS BECOMING STRONGER THAT WIDESPREAD SUB FREEZING
TEMPERATURES ARE LIKELY FRIDAY NIGHT.

ON SUNDAY THE MODEL CONSENSUS HAS SLIGHT CHANCE POPS FOR MUCH OF THE
AREA. THE MODELS BRING A WEAK DISTURBANCE THROUGH THE AREA ON THE
BACK SIDE OF THE DEPARTING CANADIAN HIGH. MOISTURE IS QUITE LIMITED
AND THE FORCING IS WEAK SO THE POSSIBILITY DOES EXIST THAT SUNDAY
MAY REMAIN DRY. TEMPERATURES WILL AVERAGE SLIGHTLY BELOW NORMAL.

SUNDAY NIGHT/MONDAY THE MODEL CONSENSUS HAS CHANCE POPS FOR THE
ENTIRE AREA AS ANOTHER FRONT APPROACHES FROM THE PLAINS.
TEMPERATURES SHOULD AVERAGE CLOSE TO NORMAL.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1224 PM CDT MON OCT 27 2014

WARM AND BREEZY CONDITIONS WILL PREVAIL UNTIL A COLD FRONT OVER
WESTERN IOWA PUSHES THROUGH THIS EVENING. THIS FRONT WILL LIKELY
TRIGGER SCATTERED SHOWERS AND POSSIBLE THUNDERSTORMS FROM LATE
AFTERNOON THROUGH EVENING...WHICH HAS BEEN HANDLED WITH TEMPO WORDING
AND A PERIOD OF MVFR CONDITIONS FOR VISIBILITY RESTRICTIONS. THE
POTENTIAL FOR THUNDERSTORMS APPEARS TOO LIMITED TO MENTION IN THE
TAFS IN THIS TIME PERIOD...BUT WILL BE MONITORED CLOSELY FOR
AMENDMENTS. LATE TONIGHT INTO TUESDAY...CONDITIONS WILL BE VFR
WITH GUSTY WEST WINDS DEVELOPING IN THE MORNING AS A DRIER PLAINS
AIRMASS MOVES IN.


&&

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

$$

SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...08
AVIATION...SHEETS






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