Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 301144
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
644 AM CDT WED JUL 30 2014

.SYNOPSIS...
ISSUED AT 340 AM CDT WED JUL 30 2014

WATER VAPOR IMAGERY SUGGESTIVE OF UPPER LEVEL IMPULSE DIVING SE
THROUGH WI AND APPEARS TO BE REFLECTION AT SFC IN FORM OF COOL
FRONT ARCING FROM SOUTH OF GREEN BAY WI TO NORTH OF LACROSSE WI.
ISOLD SHOWERS EARLIER OVER PORTIONS OF NORTHEAST CWA HAVE
DIMINISHED WITH LINGERING MID CLOUDINESS GRADUALLY THINNING.
SURFACE RIDGE AXIS REMAINS IN PLACE FROM NORTHERN PLAINS THROUGH
THE MID MISSISSIPPI VLY. ALOFT... PATTERN UNCHANGED AND REMAINS
HIGHLY AMPLIFIED BETWEEN DEEP LONG-WAVE TROUGH OVER THE EASTERN
CONUS AND WESTERN RIDGE... WITH LOCAL AREA CONTINUING TO RESIDE IN
NW FLOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM CDT WED JUL 30 2014

PERSISTENCE FCSTING REMAINS THE WAY TO GO WITH STAGNANT NW FLOW
PATTERN SFC AND ALOFT... AND LITTLE CHANGE THERMALLY (H85 TEMPS
REMAIN AROUND 12C). THUS... TDY TO LOOK FAIRLY SIMILAR TO YSTDY
WITH PATCHY MID CLOUDS GIVING WAY TO DIURNAL CU INCREASING IN
COVERAGE DURING AFTN. EXPECT TO SEE ISOLD TO LOW END SCTD SHOWERS
AND ISOLD STORMS MAINLY FROM AROUND THE QUAD CITIES N/E WITH AID
OF WI IMPULSE SLIDING SEWD. MAY HAVE TO WATCH FOR ISOLD STRONGER
CELL WITH GUSTY WINDS AND POSSIBLY SMALL HAIL PORTIONS OF
NORTHEAST IA AND NORTHWEST IL WITH FAIRLY SIMILAR LOW CAPE/HIGH
SHEAR ENVIRONMENT TO THAT OF WI YSTDY WHICH SAW OF SPECKLING OF
SEVERE REPORTS MAINLY WIND. 0-6KM SHEAR THOUGH PROGGED NOT TO BE
AS STRONG AS ACROSS WI YSTDY (35-40 KTS)... WITH LATEST RUNS OF
RAP AND NAM SUGGESTING 25-30 KTS OF 0-6KM SHEAR NORTHEAST OF KDBQ-
KVYS LINE. THIS PLENTY STRONG ENOUGH /SEASONALLY MODERATE/ TO
SUPPORT A FEW MORE ROBUST AND ORGANIZED CELLS ESPECIALLY WHEN
MODIFIED FCST SOUNDINGS USING TEMPS IN UPPER 70S AND DEWPTS IN
MID/UPPER 50S YIELD SBCAPES AROUND 1000-1300+ J/KG. NICE INVERTED
V-TYPE SOUNDING WITH VERY STEEP LOW LEVEL LAPSE RATES SFC-700 MB
OF 8.5-10C WITH LOTS OF SUB CLOUD DRY AIR FOR EVAPORATIVE COOLING
TO ENHANCE DOWNDRAFTS. GREATEST POTENTIAL FOR STRONGER CONVECTION
AND BEST COVERAGE LOOKS TO BE JUST E/NE OF CWA WITH AID OF ENTRANCE
REGION OF 70+ KT H5 JET MAX AND LOW LEVEL CONVERGENCE ALONG SFC FRONT
POSSIBLY LAKE ENHANCED.

ANY CONVECTION TO GRADUALLY DIMINISH BY LATE EVE AND EARLY OVRNGT
FOLLOWED BY MAINLY CLEAR/PTCLDY SKIES AND LIGHT WINDS. COULD SEE
SOME PATCHY FOG ESPECIALLY ANY AREAS THAT SEE RAINFALL. LOWS WILL
BE SIMILAR WITH COOLEST READINGS (LOW/MID 50S) IN RIVER VALLEYS
AND LOW LYING AREAS... WHILE ELSEWHERE EXPECT LOWS IN THE UPPER 50S
TO AROUND 60F.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 340 AM CDT WED JUL 30 2014

BELOW NORMAL TEMPERATURES FOR MUCH OF THIS PERIOD WITH BETTER
CHANCES OF RAIN NEXT WEEK.

THURSDAY THROUGH SATURDAY...HIGHLY AMPLIFIED BLOCKED PATTERN TO
REMAIN LOCKED IN PLACE DURING THIS TIME FRAME. DEEP TROUGH IN THE
EAST WILL ALLOW FOR SHORT WAVES TO DIVE SOUTHEAST IN THE NORTHWEST
FLOW ALOFT. WILL HAVE CHANCE POPS DURING THIS TIME WITH THE HIGHEST
POPS IN OUR NORTHERN AND EASTERN CWA. NOT MUCH CHANGE IN THE
TEMPERATURES WITH HIGHS IN THE UPPER 70S/LOWER 80S AND LOWS IN THE
UPPER 50S/LOWER 60S.

SUNDAY THROUGH TUESDAY...THE BLOCKY PATTERN BREAKS DOWN DURING THIS
TIME FRAME AS A PIECE OF STRONG ENERGY FROM A DEEP CLOSED LOW SOUTH
OF THE ALEUTIANS PUSHES INTO THE NORTHERN ROCKIES...AND FLATTENS
THE WESTERN RIDGE. THIS SETS UP A ZONAL FLOW BRIEFLY EARLY NEXT
WEEK. THIS SHOULD TRIGGER PERIODIC THUNDERSTORM COMPLEXES IN OR NEAR
THE DVN CWA AS A STRONG FRONTAL BOUNDARY WILL MEANDER OVER THE
MIDWEST...ON THE EDGE OF THE HEAT DOME CENTERED IN THE SOUTHERN
ROCKIES/SOUTHERN PLAINS. FOR NOW WILL HAVE CHANCE POPS EARLY NEXT
WEEK WITH THE WARMEST DAY ON MONDAY...WITH HIGHS IN THE 80S.

BEYOND THIS THE ECMWF LOOKS INTERESTING DEVELOPING A CLOSED LOW AND
TRACKING IT ACROSS THE MIDWEST LATER NEXT WEEK PROVIDING SOAKING
RAINS FOR SOME AREAS. THIS TO BE FOLLOWED BY ANOTHER CHILLY AIRMASS
DROPPING INTO THE UPPER MIDWEST BEHIND THE SYSTEM. BELOW NORMAL
TEMPERATURES APPEAR LIKELY AT LEAST THROUGH THE MIDDLE OF AUGUST.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 636 AM CDT WED JUL 30 2014

AN UPPER LEVEL DISTURBANCE WILL TRIGGER SOME SHOWERS FROM MID
AFTERNOON INTO EARLY EVENING AND KEPT PREVIOUS SHIFTS MENTION OF
PROB30 AT CID...DBQ AND MLI. AN ISOLATED STORM IS POSSIBLE BUT
CONFIDENCE TOO LOW FOR MENTION. ANY SHOWERS TO DISSIPATE BY LATE
EVE INTO EARLY OVERNIGHT FOLLOWED BY CLEAR TO PARTLY CLOUDY SKIES
AND LIGHT WESTERLY WINDS. PATCHY FOG WILL BE POSSIBLE LATE TONIGHT
ESPECIALLY IN AREAS THAT SEE ANY RAINFALL.

&&

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

$$

SYNOPSIS...MCCLURE
SHORT TERM...MCCLURE
LONG TERM...HAASE
AVIATION...05




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