Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 020832
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
332 AM CDT TUE JUN 2 2015

.SYNOPSIS...
ISSUED AT 332 AM CDT TUE JUN 2 2015

A PERSISTENT RIDGE OF HIGH PRESSURE REACHING FROM THE GREAT LAKES SW
ACROSS NORTHERN IL...EASTERN IA INTO N CENTRAL MO WAS CONTINUING
THE COOL DRY CONDITIONS OVER THE AREA EARLY THIS MORNING.
SATELLITE IMAGERY AND SURFACE OBSERVATIONS SHOWED A DECK OF LOW
CLOUDS DEVELOPING OVER EASTERN IA...BUT THE MAIN AREA CONTINUED TO
SKIRT THE FORECAST AREA TO THE SOUTH AND SOUTHEAST. HIGH CLOUDS
SPEWING OFF CONVECTIVE COMPLEXES IN THE NORTHERN PLAINS WERE
RAPIDLY APPROACHING...AS CLOSE AS SOUTHERN MN AND WESTERN IA.
LIGHT FOG WAS BEING REPORTED OVER SE IA AND NE MO...WHERE
DEWPOINTS WERE IN THE 50S AND WINDS WHERE LIGHTEST UNDER THE RIDGE
AXIS. OVER THE REST OF THE FORECAST AREA...A LIGHT EASTERLY FLOW
WAS PROVIDING A DRIER GREAT LAKES AIRMASS WITH DEWPOINTS ONLY IN
THE 30S AND 40S OVER NORTHERN IL. ACTUAL TEMPERATURES RANGED FROM
THE LOWER 40S OVER FAR NW IL...TO THE MID 50S IN SE IA.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 332 AM CDT TUE JUN 2 2015

TEMPERATURES ARE THE PRIMARY CHALLENGE AS THE SURFACE RIDGE
GRADUALLY RETREATS EASTWARD UNDER BUILDING HEIGHTS AND WARMING
TEMPERATURES ALOFT. IN THE NEAR TERM...HAVE ADDED PATCHY FOG FOR THE
EARLY PREDAWN HOURS...WHERE TEMP/DEWPOINT DEPARTURES CONTINUE TO
NARROW AND WINDS REMAIN LIGHT. THIS FOG SHOULD BE RATHER SHALLOW AND
RAPIDLY DISSIPATE SHORTLY AFTER SUNRISE. OTHERWISE...CI FROM THE
PLAINS CONVECTION WILL OVERSPREAD MUCH OF THE AREA THIS MORNING TO
PROVIDE FILTERED SUNSHINE. AT THE SAME TIME...LOW LEVEL WINDS
GRADUALLY VEERING FROM THE E TO MORE S-SE MAY ALLOW THE PERSISTENT
STRATOCU DECK TO ADVANCE BACK NORTH INTO NE MO AND POSSIBLY SE IA
THIS MORNING AS SUGGESTED BY THE WRF RH FIELDS. THUS WILL HAVE MORE
CLOUDS ACROSS THE WEST AND SOUTH TODAY WITH MOSTLY SUNNY SKIES EAST.
850 MB TEMPERATURES CLIMBING ROUGHLY 2 TO 4 DEGREES ABOVE THOSE
OBSERVED AT 02/00Z SHOULD BE ENOUGH TO OFFSET THE FILTERED
SUNSHINE AND HAVE KEPT HIGHS CLOSE TO GUIDANCE...FROM THE LOWER TO
MID 70S.

TONIGHT...LIGHT SOUTHERLY WINDS AND RISING DEWPOINTS...ALONG WITH
POSSIBLY ANOTHER ROUND OF HIGH CLOUDS STREAMING OFF PLAINS
CONVECTION...WILL LEAD TO WARMER TEMPERATURES THAN THE PAST SEVERAL
NIGHTS. MODELS MAY...HOWEVER...BE TOO FAST WITH THE AMOUNT OF LOW
LEVEL MOISTURE RETURN AND WILL CONTINUE TO TREND TOWARD THE COOLER
SIDE OF MOS GUIDANCE MINS FROM AROUND 50 NORTHEAST TO THE MID 50S
SOUTH AND SW.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 332 AM CDT TUE JUN 2 2015

WEDNESDAY...CONVECTION WILL FORM OVER THE CENTRAL PLAINS STATES TUE
NIGHT IN RESPONSE TO MOISTURE FLUX-CONVERGENCE ON THE NOSE OF A
STRENGTHENING NOCTURNAL LOW-LEVEL JET. SYNOPTIC FORCING FOR ASCENT
TUE NIGHT INTO WED MORNING IS LIMITED. A WEAKENING LLJ WED
MORNING...LIGHT 850-300MB MEAN WIND FLOW OF ONLY 10-15 KTS...AND
MARGINAL INSTABILITY OF LESS THAN 500 J/KG MUCAPE DOWNSTREAM OF THE
POTENTIAL MCS SHOULD ALL CONTRIBUTE TO LIMITED EASTWARD PROGRESS OF
THE THUNDERSTORM COMPLEX.

HAVE SLIGHT CHANCES FOR SHOWERS/STORMS ACROSS THE FAR WESTERN
SECTION OF THE FORECAST AREA THROUGH THE DAY WITH A LITTLE BETTER
CHANCE OVERNIGHT...BUT STILL NOT LIKELY...MAINLY WEST OF THE
MISSISSIPPI RIVER. HIGHS SHOULD REACH THE UPPER 70S TO NEAR 80
F...SE WINDS WILL BE STEADY BETWEEN 10-15 MPH.

THURSDAY...LOWER 80S FOR HIGHS...WINDS WILL BE VERY LIGHT AS
PRESSURE GRADIENT REFOCUSES ACROSS THE PLAINS. ISOLATED TO SCATTERED
DAYTIME THUNDERSTORMS ARE POSSIBLE. GFS/ECMWF ARE PROJECTING DECENT
CONDITIONAL INSTABILITY OF 1000-2000 J/KG MUCAPE BY THE AFTN.
CURRENT FORECAST HAS A 20-40 POP GRADIENT FROM EAST-TO-WEST THROUGH
THE DVN CWA. SEVERE WEATHER POTENTIAL IS LOW AT THIS TIME.

THURSDAY NIGHT...MODELS ARE DISPLAYING MANY DIFFERENT SCENARIOS IN A
WEAKLY FORCED SYNOPTIC REGIME. AT LEAST SOME SCATTERED STORMS LOOK
LIKELY BUT EXACTLY WHERE IN THE FORECAST AREA IS THE QUESTION. THE
FAVORED ZONE IS AGAIN WEST OF THE MISSISSIPPI RIVER AND A LITTLE MORE
LIKELY ALONG AND SOUTH OF I-80. IT WILL DEPEND UPON WHERE THE NOSE
OF THE 850MB NOCTURNAL LLJ SETS UP. AT THE MOMENT...SOUTH-CENTRAL
IOWA/NW MISSOURI/SE NEBRASKA HAVE BETTER CHANCES FOR THUNDERSTORMS
OR A POSSIBLE MCS.

PWAT VALUES AROUND 1.50 INCHES ARE SUPPORTIVE OF LOCALIZED HEAVY
RAINFALL IN ANY STORMS THAT FORM IN THE DVN CWA.

FRIDAY...MID-LEVEL RIDGING EXPANDING OVER THE PLAINS WILL CAUSE
500MB WINDS TO VEER TO THE NW. DAYTIME INSTABILITY AND POSSIBLE
LINGERING OUTFLOW BOUNDARIES WARRANT ISOLATED TO SCATTERED
THUNDERSTORM CHANCES. SFC WINDS WILL DEVELOP OUT OF THE NE AS HIGH
PRESSURE BUILDS INTO THE GREAT LAKES. CONSEQUENTLY...HIGHS ARE
FORECAST TO RANGE FROM THE LOWER 70S OVER THE FAR NORTH TO THE LOWER
80S IN THE FAR SOUTH.

SATURDAY AND SUNDAY...TEMPS LOOK SEASONAL IN THE 70S. BOTH THE GFS
AND ECMWF ARE FORECASTING A STRONG SHORTWAVE TROUGH TO DIVE
SOUTHEASTWARD INTO THE UPPER MIDWEST AND GREAT LAKES SAT NIGHT INTO
SUN DRAGGING A COLD FRONT THROUGH THE AREA. THE ECMWF IS MORE ROBUST
THAN THE GFS...WHICH IN TERMS OF SENSIBLE WEATHER HAS A MUCH BETTER
CHANCE FOR SHOWERS/STORMS IN ASSOCIATION WITH THE FRONT. ALL-IN-ALL
SATURDAY LOOKS MAINLY DRY THEN HAVE 30-40 POPS SAT NIGHT/SUN MORNING.

MONDAY...SUBSIDENCE ON THE WESTERN SIDE OF THE SHORTWAVE TROUGH AND
DRIER NW WINDS SHOULD SET UP A NICE DAY WITH DRY CONDITIONS ASIDE
FROM A FEW ISOLATED SHOWERS OR SPRINKLES. EVEN THOUGH 850MB WINDS
WILL BE NORTHWESTERLY...STRONG RIDGING OVER THE PLAINS MEANS WAA
WILL OCCUR THROUGH THE DAY WITH 850MB TEMPS RISING BACK UP NEAR +16C
AND 1000-500MB THICKNESSES TO AROUND 572 DAM. CONSENSUS HIGH TEMPS
ARE IN THE UPPER 70S TO LOWER 80S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 332 AM CDT TUE JUN 2 2015

A DEVELOPING AREA OF LOW CLOUDS WITH MVFR BASES IN EAST CENTRAL IA
AND ALONG THE MS RIVER WILL IMPACT THE MLI AND BRL TERMINALS...AND
POTENTIALLY CID AS WELL EARLY THIS MORNING. TAFS HAVE BEEN UPDATED
TO INCLUDE THESE MVFR CONDITIONS DUE TO THE LOWERED CIGS...ALONG
WITH POSSIBLE GROUND FOG FORMING LATE TONIGHT INTO THE PREDAWN
HOURS IN SE IA. OTHERWISE...VFR CONDITIONS ARE EXPECTED TODAY
THROUGH TONIGHT WITH LIGHT SE WINDS.

&&

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

$$

SYNOPSIS...SHEETS
SHORT TERM...SHEETS
LONG TERM...UTTECH
AVIATION...SHEETS


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