Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 301739
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1239 PM CDT MON MAR 30 2015

.UPDATE...
ISSUED AT 1238 PM CDT MON MAR 30 2015

EFFICIENT BOUNDARY LAYER MIXING AND DRY LOW-LEVEL AIR WITH
DEWPOINTS IN THE 20S HAS RESULTED IN A RAPID CLIMB IN SFC TEMPS.
BUMPED UP HIGHS FOR TODAY A FEW DEGREES TO ACCOUNT FOR THIS AS
MIXING WILL LIKELY REACH TO NEAR 800 MB LATER THIS AFTN.

&&

.SYNOPSIS...
ISSUED AT 300 AM CDT MON MAR 30 2015

AT 3 AM CDT...TEMPERATURES ACROSS THE AREA WERE IN THE 30S TO
LOWER 40S IN PARTS OF THE MISSISSIPPI RIVER VALLEY. UNDER A
MOSTLY CLEAR SKY...A WESTERLY WIND GENERALLY RANGED FROM 5 TO 10
MPH.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 300 AM CDT MON MAR 30 2015

THE MAIN FORECAST ISSUE IN THE SHORT TERM PERIOD IS FIRE WEATHER
CONCERNS THIS AFTERNOON...WITH DETAILS IN THE FIRE WEATHER SECTION BELOW.

EXPECT A WARM AND BREEZY DAY...WITH MAINLY DRY CONDITIONS. THE
POSSIBLE EXCEPTION WOULD BE THIS EVENING IN THE FREEPORT AREA AS
WEAK WAVE PASSES IN THE VICINITY. THERE IS A LOW PROBABILITY OF
SOME LIGHT RAIN OR SPRINKLES.

BUFR SOUNDINGS SUGGEST A DEEP MIXED LAYER TO 850-800MB THIS
AFTERNOON...WITH A DECENT UNIDIRECTIONAL SW WIND PROFILE. HAVE
BUMPED UP SUSTAINED WIND SPEEDS AND GUSTS A BIT TODAY...WITH GUSTS
AROUND 25 KTS IN EASTERN IOWA. ALSO LOWERED DEWPOINTS
TODAY...ESPECIALLY WEST WHERE THE DEEPER MIXING IS FAVORED. HIGHS
AROUND 60 NORTHEAST TO 70 WEST LOOK REASONABLE. LOWS TONIGHT
EXPECTED TO SETTLE MAINLY IN THE 40 TO 45 DEGREE RANGE.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 300 AM CDT MON MAR 30 2015

MAIN FORECAST PROBLEM FOR THE LONG TERM FORECAST ARE TWO SYSTEMS
MOVING THROUGH THE AREA.  THE FIRST SYSTEM IS FORECAST TO MOVE
THROUGH MID WEEK AND COULD LEAD TO SOME THUNDERSTORMS...THE OTHER
SYSTEM AT THE BEGINNING OF NEXT WEEK AND COULD LEAD TO SOME RAIN AND
EVEN A RUMBLE OF THUNDER ACROSS THE AREA.

TUESDAY INTO WEDNESDAY...A CLIPPER SYSTEM WILL BE MOVING THROUGH THE
GREAT LAKES REGION AT THE BEGINNING OF THE FORECAST PERIOD.
GUIDANCE...WITH THE EXCEPTION OF THE ECMWF...KEEPS ALL OF THE QPF
OUT OF THE CWA.  BELIEVE THAT MOST OF THE QPF WILL BE OUT OF THE
AREA WITH THE CLIPPER SYSTEM ORIENTED RATHER PARALLEL TO THE FLOW.
SO NO POPS TUESDAY.  BEHIND THIS CLIPPER A RIDGE BUILDS INTO THE
AREA AND SHOULD LEAD TO WARM TEMPERATURES AN MOISTURE ADVECTING INTO
THE AREA.

WEDNESDAY INTO THURSDAY...A SHORT WAVE TROUGH IS FORECAST TO MOVE
ACROSS FAR NORTHERN PORTIONS OF THE CONUS AND SOUTHERN CANADA.  A
SURFACE LOW IS EXPECTED TO MOVE ACROSS THE SAME AREA.  AN ATTENDANT
COLD FRONT IS FORECAST TO MOVE THROUGH OUR AREA AND LEAD TO THE
DEVELOPMENT OF SHOWERS AND EVEN THUNDERSTORMS LATE ON WEDNESDAY AND
INTO THURSDAY MORNING.  THE GFS HAS SLOWED DOWN SLIGHTLY FROM THE
12Z RUN AND IS CLOSER TO AGREEMENT WITH THE ECMWF...BUT REGARDLESS
IS FASTER THAN THE REST OF THE MODELS.  SPC HAS WESTERN IA IN A DAY
3 SLIGHT AND OUR IOWA AND MO ZONES IN A MARGINAL RISK FOR SEVERE
WEATHER ON WEDNESDAY.  LOOKING AT THE GUIDANCE...SLOWER SOLUTIONS
LIKE THE ECMWF...SUGGEST THAT OUR OVERALL THREAT FOR SEVERE WEATHER
WOULD BE LOW...THE REMNANTS OF STRONG TO POSSIBLY SEVERE
THUNDERSTORMS WOULD BE MOVING INTO THE AREA AFTER 06Z WHEN
INSTABILITY IS LOW.  WITH THE GFS BEING SLIGHTLY FASTER THERE IS A
CHANCE THAT OUR WESTERN ZONES COULD SEE SOME STRONG THUNDERSTORMS
AND EVEN POSSIBLY A MARGINALLY SEVERE HAIL EVENT.  HOWEVER...IT
APPEARS THAT THE SYSTEM WILL LIKELY BE CLOSER TO THE ECMWF SOLUTION.

DEEP LAYER SHEAR IS AOA 30-40 KNOTS THROUGH THE ENTIRE EVENT. THIS
SHEAR IS SUFFICIENT FOR ORGANIZED CONVECTION...LIKELY MULTICELL
STORMS. AFTER 06Z THURSDAY A STRONG H85 LLJ DEVELOPS AND LEADS TO
STRONG LOW LEVEL SHEAR ACROSS THE AREA...ESPECIALLY EAST OF THE
MISSISSIPPI RIVER.  WITH INSTABILITY WANING...THE MAIN THREAT FROM
THESE THUNDERSTORMS MAY BE SOME GUSTY WINDS AND CG.  TIMING OF THE
FROPA AND ANY ADDITIONAL INCREASES IN INSTABILITY COULD LEAD TO
DIFFERENT THREATS COME WEDNESDAY NIGHT.  IT WILL BE IMPORTANT TO PAY
ATTENTION TO FUTURE FORECASTS ON THIS EVENT.

WITH THE WAVE MOVING TO THE EAST...THE COLD FRONT STALLS OUT TO OUR
SOUTH AND WILL LEAD TO RAIN THURSDAY ACROSS SOUTHERN PORTIONS OF THE
CWA.  THIS WILL PERSIST THROUGH FRIDAY WHEN ANOTHER WAVE CROSSES THE
CENTRAL UNITED STATES AND MOVES THE FRONT OUT OF THE AREA.  THE
WEEKEND LOOKS PLEASANT BUT COOLER THAN MID WEEK THIS WEEK.

EARLY NEXT WEEK...THERE ARE MAJOR DIFFERENCES BETWEEN THE GFS AND
ECMWF.  THE SUPER BLEND HAS PRECIP ACROSS OUR AREA WITH RAIN BEING
THE DOMINANT PRECIP TYPE.  WITH THE DISCREPANCIES BETWEEN THE
MODELS...I HAVE LOW CONFIDENCE ON THIS EVENT OVERALL.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1238 PM CDT MON MAR 30 2015

VFR CONDITIONS WILL PREVAIL DURING THIS TAF FORECAST PERIOD. WSW
WINDS WILL GUST BETWEEN 20-25 KTS THROUGH THE AFTN BEFORE
SUBSIDING. A WIND SHIFT TO THE NW IS FORECAST AFTER MIDNIGHT
TONIGHT BUT WINDS WILL CONTINUE TO DECREASE INTO TUESDAY MORNING.

&&

.FIRE WEATHER...
ISSUED AT 300 AM CDT MON MAR 30 2015

SLIGHTLY HIGHER WIND SPEEDS AND LOWER DEWPOINTS THIS AFTERNOON...HAVE
YIELDED MINIMUM RELATIVE HUMIDITY VALUES OF 20 TO 25 PERCENT OVER
MOST OF OUR IOWA COUNTIES...AND POSSIBLY EXTENDING INTO WEST
CENTRAL ILLINOIS. GRASSLAND FIRE DANGER INDEX VALUES IN THE VERY
HIGH CATEGORY ARE FORECAST OVER MOST OF EASTERN IOWA INTO WEST
CENTRAL ILLINOIS THIS AFTERNOON. DRY FUELS AND RH VALUES CERTAINLY
MEET RED FLAG WARNING CRITERIA. HOWEVER...WIND SPEEDS ARE
MARGINAL. WILL ISSUE A SPECIAL WEATHER STATEMENT TO OUTLINE
ELEVATED RISK OF RAPID FIRE GROWTH...IN ADDITION TO THE HAZARDOUS
WEATHER OUTLOOK.

&&

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

$$

UPDATE...UTTECH
SYNOPSIS...RP KINNEY
SHORT TERM...RP KINNEY
LONG TERM...GIBBS
AVIATION...UTTECH
FIRE WEATHER...RP KINNEY






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