Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 160918
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
418 AM CDT WED APR 16 2014

.SYNOPSIS...
ISSUED AT 406 AM CDT WED APR 16 2014

HIGH PRESSURE RIDGE HAS MOVED INTO THE OHIO VLY WHILE A 998 MB SFC
CYCLONE WAS LOCATED SOUTH OF PIERRE SD AT 07Z. SOUTHEAST WINDS
ARE STRENGTHENING OVER THE AREA IN TIGHTENING PRESSURE GRADIENT
RESULTING IN STEADY TO RISING TEMPS. PATTERN ALOFT FEATURES FAST
SEMI-ZONAL FLOW OVER REGION AHEAD OF SHORTWAVE TRAVERSING NORTHERN
ROCKIES.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 406 AM CDT WED APR 16 2014

CRITICAL FIRE WEATHER AND WIND ADVISORY CONCERNS DOMINATE THE FCST.

SFC CYCLONE OVER SD WILL MOVE EAST INTO WI BY EARLY THURSDAY AM.
TRAILING COLD FRONT WILL MOVE INTO CWA LATER THIS EVENING AND
MOVE EAST AND SHOULD BE NEAR OR JUST EAST OF MISSISSIPPI RIVER
BY 12Z THURSDAY. WARM SECTOR OF SYSTEM IS MOISTURE STARVED AND
THUS MOST OF PCPN THAT OCCURS DURING PERIOD WILL BE RIGHT AHEAD
AND NORTH OF SFC CYCLONE TRACK. WILL THOUGH HAVE SMALL CHCS
FOR LIGHT RAIN WITH FRONT TONIGHT MAINLY NORTHEAST IA BEING IN
CLOSER PROXIMITY TO PV ANOMALY AND VORTICITY ADVECTION.

VERY STRONG LOW LEVEL JET WITH 850 MB WINDS OF 50-60 KTS TO FOCUS
MAINLY WEST OF CWA THIS AM THEN SHIFT INTO AREAS WEST OF
MISSISSIPPI RIVER THIS AFTN BUT WEAKENING TO NEAR 40 KTS.
NONETHELESS...TIGHTENING PRESSURE GRADIENT AND DEEP MIXING TAPPING
STRONGER WINDS ALOFT SHOULD GENERATE SUSTAINED SOUTHEAST TO SOUTH
WINDS AT 20-25 KTS WITH GUSTS AROUND 35 KTS... CLOSE TO WIND
ADVISORY CRITERIA WHICH WILL NEED TO BE MONITORED IN CASE AN
ADVISORY BECOMES NEEDED...BUT ENOUGH UNCERTAINTY WITH CLOUDS AND
POTENTIAL IMPACTS ON MIXING AND NOTED WEAKENING TRENDS ON WINDS
ALOFT FROM LATEST RUC AND NAM TO HOLD OFF ON ISSUING ATTM.

STRONG WINDS WILL AID IN ELEVATED FIRE DANGER TODAY...WITH MAIN
CHALLENGE BEING LOW LEVEL MOISTURE AND MODELS HANDLING WHICH WILL
LOOM LARGE AS TO WHETHER RED FLAG WARNING CRITERIA IS ACHIEVED IN
SOME AREAS. DEEP MIXING TO AT OR ABOVE 800 MB IF REALIZED FROM
NAM/RUC SOUNDINGS WOULD YIELD SUBSTANTIAL DROP IN DEWPTS INTO THE
TEENS TO LOWER 20S ALL BUT FAR WESTERN CWA THIS AFTN. AND THESE
LOW DEWPTS CERTAINTLY SHOW UP IN LOOKING BACK AT UPSTREAM OBS IN
SIMILAR REGIME YSTDY. UNCERTAINTY WITH HOW MUCH RECENT HEAVY RAINS
AND CONTINUED GREENING UP TO IMPACT OR OFFSET DRYING ATTENDANT TO
DEEP MIXING. THIS IS DISCUSSED FURTHER IN FIRE WEATHER SECTION BELOW.

HIGHS TODAY WITH MIXING AND PROGGED LOW LEVEL THICKNESS AND
VERIFICATION FROM YSTDY ALONG WITH BOUTS OF MID/HIGH CLOUDINESS SUPPORT
LOWERING MAXES FEW DEGS ESPECIALLY NORTHEAST 1/3-1/2. OVERALL...
VERIFICATION SUPPORTS HIGHS RANGING FROM 50-55F NORTHEAST TO
LOWER 60S SOUTHWEST. TEMPS MILD MOST OF TONIGHT HELD UP BY BREEZY
SOUTH/SOUTHWEST WINDS WITH TEMPS FALLING LATE WITH FRONTAL
PASSAGE WITH MID 30S WEST/NORTHWEST TO LOWER 40S EAST/SOUTHEAST.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 406 AM CDT WED APR 16 2014

FORECAST FOCUS IN THE EXTENDED IS ON CONTINUED BELOW NORMAL
TEMPERATURES THROUGH THE REST OF THE WORK WEEK WITH SMALL PCPN
CHANCES ACROSS THE SOUTHEAST THURSDAY NIGHT/FRIDAY MORNING.
TEMPERATURES TO RETURN TO NORMAL THIS WEEKEND AND POSSIBLY ABOVE
NORMAL EARLY NEXT WEEK.

THURSDAY...WEAK COLD FRONT TO BE JUST EAST OF CWA IN THE MORNING
WITH PARENT LOW LIFTING NORTHEAST INTO THE GREAT LAKES. LINGERING
CLOUDS...WEST WINDS...AND MIXING TO AROUND 900MB WILL KEEP
TEMPERATURES WELL BELOW NORMAL WITH AFTERNOON READINGS IN THE UPPER
40S NORTH TO MIDDLE 50S SOUTH. ONE CONCERN IS CLOUD TRENDS AND IF
CLOUDS CLEAR OUT...THAN FORECAST MAX TEMPS MAY BE A FEW DEGREES TOO
COLD.

THURSDAY NIGHT-FRIDAY...SHORTWAVE TO TRACK OVER THE SOUTHERN PLAINS
LIFTING NORTHEAST NEAR THE CWA AROUND MIDNIGHT. LOW LEVEL
CONVERGENCE AND MOISTURE TRANSPORT INCREASES ACROSS THE FAR
SOUTHEAST WITH LIGHT RAIN SHOWERS BREAKING OUT MAINLY SOUTH AND EAST
OF A LINE FROM KIRKSVILLE MISSOURI TO PRINCETON ILLINOIS. MOISTURE
AVAILABILITY IS VERY LIMITED SO QPF AMOUNTS WILL BE A FEW HUNDREDTHS OF
AN INCH. ONE THING OF NOTE IS THE LATEST NAM SOLUTION HAS A
NON-EVENT FOR THIS PERIOD WHICH WAS MUCH DIFFERENT THAN ITS PREVIOUS
RUN. ANOTHER VERY INTERESTING THING IS THAT THE NEW 00Z NAM/GFS BOTH
HAVE A SHORTWAVE COMING DOWN FROM CANADA IMPACTING THE CWA WITH
CLOUDS AND PCPN CHANCES FRIDAY. THE NON-AMERICAN SOLUTIONS
(ECMWF/GEM/UKMET) ALL SAY OTHERWISE AND HAVE DRY FORECASTS. SIDED
WITH THE NON-AMERICAN SOLUTIONS GIVEN THAT THE NAM/GFS HAVE BEEN
NOTORIOUSLY TOO MOIST IN THE LOW LEVELS THIS SPRING. HIGH
TEMPERATURES FRIDAY TO BE A LITTLE WARMER THAN THURSDAY BUT STILL
BELOW NORMAL.

THIS WEEKEND...MODELS CONTINUE TO SHOW A STORM SYSTEM TRACKING
ACROSS SOUTHERN CANADA WITH A COLD FRONT MOVING ACROSS THE MIDWEST.
AHEAD OF THIS FRONT...TEMPERATURES WILL WARM NICELY WITH 85H
TEMPS PROGGED TO BE IN THE +6 TO 10C RANGE BY 00Z SUNDAY. HIGHS OVER
THE WEEKEND TO BE IN UPPER 50S/LOW 60S SATURDAY AND IN THE 60S AREA
WIDE ON SUNDAY. FORCING AND LOW LEVEL MOISTURE INCREASES SUNDAY
AHEAD OF COLD FRONT WITH LIGHT TO POSSIBLY MODERATE RAIN FALLING
SOMETIME DURING THE DAY. MODEL CONSENSUS HAS CHANCE POPS AT THIS
TIME FOR SUNDAY.

EARLY NEXT WEEK...WARM AND DRY CONDITIONS WILL BE FOUND AS HIGH
PRESSURE DRIFTS ACROSS THE MIDWEST. TEMPERATURES TO AVERAGE ABOVE
NORMAL WITH HIGHS WELL INTO THE 60S AND LOWER 70S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1137 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. WEDNESDAY EVENING THE LOW
WILL LIFT NORTHEAST INTO WISCONSIN...DRAGGING A COLD FRONT THROUGH
CENTRAL IOWA. A FEW SHOWERS JUST AHEAD OF THE FRONT MAY MAKE IT
INTO THE KCID VICINITY JUST BEFORE 06Z. WINDS WILL ALSO BE
DECREASING AHEAD OF THE FRONT...BUT SHOULD REMAIN GUSTY.

&&

.FIRE WEATHER...
ISSUED AT 406 AM CDT WED APR 16 2014

SOUTHEAST TO SOUTH WINDS WILL INCREASE TO NEAR ADVISORY CRITERIA
AT TIMES LATE THIS MORNING THROUGH AFTERNOON WITH SUSTAINED SPEEDS
AT 20-30 MPH AND GUSTS TO NEAR 40 MPH. MAIN QUESTION/CONCERN IS
WITH SURFACE DEW POINTS AND SUBSEQUENT RELATIVE HUMIDITY VALUES.
MODEL GUIDANCE SUPPORTIVE OF DEW POINTS IN THE 20S TO LOWER 30S
WHICH COMBINED WITH TEMPS IN THE 50S TO LOWER 60S WOULD YIELD
RELATIVE HUMIDITY VALUES MAINLY IN THE 30S. HOWEVER...DEEP MIXING
AIDED BY SOUTHEAST FETCH OFF DEPARTING HIGH PRESSURE RIDGE WOULD
SUPPORT SUBSTANTIALLY LOWER DEW POINTS AND RELATIVE HUMIDITY VALUES
IN THE TEENS AND 20S. ALSO ADDING TO THE UNCERTAINTY IS DEGREE OF
IMPACTS IF ANY OF RECENT HEAVY RAINS AND CONTINUED GREENING UP.
IF THE LOWER VALUES OCCUR THEN IT WOULD LEAD TO VERY HIGH TO EXTREME
GRASSLAND FIRE DANGER INDEX VALUES AND LIKELY NECESSITATE RED FLAG
WARNING PORTIONS OF AREA. ENOUGH UNCERTAINTY PRECLUDES ISSUANCE OF
RED FLAG WARNING AT THIS TIME... BUT WILL NEED TO MONITOR DEW
POINT AND RELATIVE HUMIDITY LEVELS CAREFULLY FOR POTENTIAL OF
NEEDING HEADLINE. FIRE DANGER ELEVATED TO POSSIBLY HIGH OVER DRY
GRASSES AND CURED VEGETATION.

&&

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

$$

SYNOPSIS...05
SHORT TERM...05
LONG TERM...GROSS
AVIATION...DLF
FIRE WEATHER...05





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