Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 152314
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
614 PM CDT TUE APR 15 2014

.SYNOPSIS...
ISSUED AT 337 PM CDT TUE APR 15 2014

COLD CANADIAN AIRMASS UNDER A RIDGE AXIS FROM EASTERN TX TO WI WAS
PRODUCING AN EARLY MARCH-LIKE DAY OVER THE FORECAST AREA WITH
AFTERNOON TEMPERATURES IN THE 30S TO LOWER 40S UNDER NEAR FULL
SUNSHINE. UPPER AIR ANALYSIS FROM THIS MORNING INDICATED A BROAD NW
FLOW FROM THE WEST COAST TO A LONGWAVE TROUGH FROM THE GREAT LAKES
TO THE CENTRAL GULF STATES. A SHORTWAVE WAS EVIDENT IN THE NW FLOW
OVER ID AND WESTERN MT. LOW PRESSURE WAS DEVELOPING IN RESPONSE
OVER EASTERN MT. THIS SHORTWAVE AND ASSOCIATED LOW WILL MIGRATE
E-SE PASSING THROUGH SOUTHERN MN OR NORTHERN IA WED NIGHT. THE
TIGHT PRESSURE GRADIENT AND STRONG LOW LEVEL JET WELL IN ADVANCE
WILL CREATE WINDY AND SOMEWHAT WARMER CONDITIONS WEDNESDAY.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 337 PM CDT TUE APR 15 2014

PRIMARY CHALLENGE IS THE WINDY CONDITIONS DEVELOPING WEDNESDAY AND
THE UNCERTAINTIES IN CRITICAL LOW LEVEL MOISTURE PROFILES.

TONIGHT...CLEAR SKIES AND VERY DRY AIR WILL PROVIDE ANOTHER CHILLY
NIGHT...WITH LOWS IN THE 20S NORTH TO AROUND 30 SOUTH DURING THE
FIRST HALF OF THE NIGHT BEFORE SURFACE WINDS BEGIN TO RESPOND TO
THE APPROACHING LOW IN THE PLAINS. WITH DEWPOINTS ONLY IN THE
TEENS...WILL BE COUNTING ON THE HIGH CLOUDS ADVANCING FROM THE PLAINS
TO SUPPRESS THE RADIATIONAL COOLING AND PREVENT LOWS FROM DROPPING
EVEN FURTHER.

WEDNESDAY...SOUTH WINDS SHOULD INCREASE TO 20 TO 30 MPH BY MID
MORNING WITH GUSTS INTO THE 40S POSSIBLE BY AFTERNOON...ESPECIALLY
IF MODEL INDICATED 850 MB WINDS AS HIGH AS 50 TO 60 KTS ARE
CORRECT. A WIND ADVISORY MAY BE NEEDED. STILL SOME UNCERTAINTY AND
THE ANTICIPATED THICKENING MID AND HIGH CLOUDS MAY ALSO LIMIT THE
MIXING AND INTENSITY OF WIND GUSTS...SO WILL HOLD OFF ON HEADLINES
AT THIS TIME. THE WARM ADVECTION...HOWEVER...IS NOT NEARLY AS
STRONG AS THE PAST FEW STORM SYSTEMS AND MIXING TO 850 MB TO 800
MB WOULD ONLY YIELD HIGHS IN THE UPPER 50S TO LOWER 60S. ANOTHER
LARGE UNCERTAINTY...CRITICAL FOR FIRE WEATHER...IS THE AMOUNT OF
LOW LEVEL MOISTURE. FORECAST MODELS HAVE HAD A POOR HANDLE ON
MOISTURE AND MIXING IN SIMILAR SCENARIOS THIS SPRING...AND
CURRENTLY SHOW DEWPOINTS IN THE 30S FOR TOMORROW...WHEREAS THE
UPSTREAM AIRMASS IN THE PLAINS HAS AGAIN MIXED DEWPOINTS IN THE
TEENS AND 20S. IF THIS WERE TO HAPPEN...RH VALUES MAY BE LOW
ENOUGH TO WARRANT A RED FLAG WARNING...AS DISCUSSED IN THE FIRE
WEATHER DISCUSSION.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 337 PM CDT TUE APR 15 2014

FORECAST FOCUS ON NEAR TO BELOW NORMAL TEMPERATURES THROUGH THE
WEEKEND THEN TRENDING ABOVE NORMAL EARLY NEXT WEEK.

WEDNESDAY NIGHT AND THURSDAY...OCCLUDING/WEAKENING STORM SYSTEM
TRACKING INTO WISCONSIN WILL KEEP THE BULK OF THE RAIN AND SNOW
NORTH OF THE DVN CWA. HOWEVER...LOCATIONS NEAR HIGHWAY 20 WILL HAVE
A SLIGHT CHANCE WEDNESDAY EVENING. ON THURSDAY A WEAK COLD FRONT
WILL ARRIVE WITH ANOTHER CHANCE OF SHOWERS ESPECIALLY IN OUR SE CWA.
MOISTURE WILL BE LIMITED AS STRONG HIGH PRESSURE RIDGE WILL EXTEND
FROM THE EAST COAST INTO THE GULF OF MEXICO. MAXIMUM TEMPERATURES ON
THURSDAY WILL RANGE FROM THE UPPER 40S NW TO THE MID 50S SE.

THURSDAY NIGHT THROUGH FRIDAY NIGHT...HIGH PRESSURE WILL BE BUILDING
INTO THE REGION WITH HIGHS IN THE 50S AND LOWS IN THE 30S.

THIS WEEKEND...STORM SYSTEM WILL BE TRACKING ACROSS SOUTHERN CANADA
WITH A SLOW MOVING COLD FRONT PUSHING ACROSS THE MIDWEST. MODIFIED
WESTERN GULF MOISTURE WILL BE PULLED NORTHWARD AHEAD OF THE
FRONT...ALLOWING FOR LIGHT TO POSSIBLY MODERATE RAIN SOMETIME ON
SUNDAY INTO SUNDAY NIGHT. MILDER TEMPERATURES CAN BE EXPECTED WITH
HIGHS PUSHING INTO THE MID 50S TO MID 60S.

EARLY NEXT WEEK...A STRONG STORM SYSTEM WILL BE ORGANIZING IN THE
NORTHERN ROCKIES WHICH WILL PULL ABOVE NORMAL TEMPERATURES INTO THE
DVN CWA. HIGHS SHOULD PUSH WELL INTO THE 60S TO LOWER 70S.

HAASE

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 603 PM CDT TUE APR 15 2014

STRONG SOUTH WINDS WILL DEVELOP BY WEDNESDAY MORNING AS LOW
PRESSURE MOVES FROM SOUTH DAKOTA INTO NORTH CENTRAL IOWA BY LATE
WEDNESDAY AFTERNOON. SOUTH WINDS AT 20 TO 25 KTS GUSTING TO AROUND
30KTS ARE EXPECTED 12Z-15Z WITH SPEEDS INCREASING TO AROUND 25KTS
WITH GUSTS AROUND 35KTS BY 17Z AND CONTINUING THROUGH THE AFTERNOON.
THERE REMAINS A CONCERN ABOUT THE POTENTIAL FOR LOW LEVEL WIND
SHEAR LATE TONIGHT AS SOUTH WINDS AROUND 2KFT INCREASE TO 40 TO
50KTS. SINCE THE INCREASE IN SPEED WITH HEIGHT WILL BE GRADUAL AND
WINDS WILL BE UNIDIRECTIONAL THROUGH THIS LAYER...THE THREAT FOR
SIGNIFICANT SHEAR STILL LOOKS MARGINAL. OTHERWISE CONDITIONS ARE
EXPECTED TO BE VFR AND DRY THROUGH LATE WEDNESDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 337 PM CDT TUE APR 15 2014

STRONG SOUTH WINDS OF 25 TO 35 MPH ARE EXPECTED OVER NORTHEAST
MISSOURI AND EASTERN IA FROM WEDNESDAY MORNING THROUGH AFTERNOON.
RELATIVE HUMIDITY VALUES WILL DROP INTO THE 30S AND POSSIBLY AS
LOW AS THE TEENS AND 20S BY AFTERNOON. IF THESE LOWER VALUES ARE
REACHED...IT WOULD LEAD TO VERY HIGH TO EXTREME GRASSLAND FIRE
DANGER INDEX VALUES. FIRE DANGER WILL BE ELEVATED AND POSSIBLY
HIGH OVER DRY GRASSES AND CURED VEGETATION.

IF FORECAST CONFIDENCE INCREASES AND SUGGESTS WIDESPREAD RELATIVE
HUMIDITY VALUES WILL INDEED DROP INTO THE TEENS AND 20S
WEDNESDAY...A RED FLAG WARNING MAY BE NEEDED FOR PORTIONS OF
EASTERN IA AND NORTHEAST MO.

&&

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

$$

SYNOPSIS...11
SHORT TERM...11
LONG TERM...HAASE
AVIATION...DLF
FIRE WEATHER...11






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