Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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000
FXUS63 KDVN 252017 CCA
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
306 PM CDT SAT APR 25 2015

.SYNOPSIS...
ISSUED AT 303 PM CDT SAT APR 25 2015

12Z UA ANALYSIS HAD A CLOSED LOW NEAR KSTJ WITH A LLJ JET FEEDING
MOISTURE INTO THE OHIO VALLEY. SATELLITE/RADAR TRENDS THROUGH MID
AFTERNOON SHOW THE RAIN RAPIDLY ENDING WITH SOME PARTIAL CLEARING
ACROSS NORTHEAST IOWA.

18Z SFC ANALYSIS JUST NORTH OF THE MISSOURI RIVER IN EASTERN
MISSOURI. DEW POINTS WERE 20S AND 30S ACROSS THE UPPER MIDWEST AND
NORTHERN GREAT LAKES WITH 40S AND 50S ELSEWHERE.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 303 PM CDT SAT APR 25 2015

THE RAIN WILL CONTINUE TO BECOME MORE SPOTTY AND END ACROSS THE FAR
EAST AND SOUTH THROUGH LATE AFTERNOON AS THE FORCING WEAKENS AND
MOVES INTO EASTERN ILLINOIS.

SOME SPRINKLES MAY BE POSSIBLE EARLY THIS EVENING IN THE FAR
EAST/SOUTH BUT MAINLY DRY CONDITIONS WILL BE SEEN ACROSS THE
REMAINDER OF THE AREA. DRY CONDITIONS AND CLEARING SKIES WILL BE
SEEN AFTER MIDNIGHT AS HIGH PRESSURE BUILDS INTO THE WESTERN GREAT
LAKES. ALTHOUGH NOT CERTAIN...SOME VERY LOCALIZED PATCHY FOG MIGHT
DEVELOP AROUND SUNRISE.

QUITE AND DRY CONDITIONS WILL BE SEEN ACROSS THE AREA ON SUNDAY WITH
HIGH PRESSURE OVER THE WESTERN GREAT LAKES. TEMPERATURES WILL
AVERAGE A LITTLE BELOW NORMAL.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 303 PM CDT SAT APR 25 2015

MODELS ARE IN GOOD OVERALL AGREEMENT WITH THE 500 HPA PATTERN BUT
DIFFERENCES IN TIMING AND PLACEMENT OF FEATURES REMAIN. THE MAIN
FORECAST CONCERNS ARE TEMPERATURES SUNDAY NIGHT THROUGH TUESDAY
MORNING AND CHANCES OF PRECIPITATION LATER IN THE PERIOD.

SUNDAY NIGHT THROUGH TUESDAY THE UPPER MIDWEST WILL BE ON THE
WESTERN EDGE OF CYCLONIC FLOW ALOFT WITH POTENTIAL REX BLOCKING OVER
THE CENTRAL PLAINS WITH HIGH PRESSURE IN THE CENTRAL MISSOURI RIVER
VALLEY AND LOW PRESSURE OVER THE TEXAS...NEW MEXICO...AND COLORADO
REGION. THE ECWMF AND CANADIAN ARE FASTER AT DEVELOPING THIS BLOCK
OVER THE PLAINS WITH THE GFS DELAYING IT UNTIL MONDAY. SURFACE HIGH
PRESSURE IS BUILDING SOUTHWARD INTO THE PLAINS FROM THE CANADIAN
PRAIRIE DURING THIS PERIOD. THE GFS BRING THE SURFACE HIGH DOWN
ACROSS EASTERN MINNESOTA AND WESTERN WISCONSIN WHILE THE GEM AND
ECWMF BRING THE SURFACE HIGH INTO THE DAKOTAS. THUS THE GFS IS A
COUPLE OF DEGREES WARMER DURING THE PERIOD WITH WEAKER COOL
ADVECTION INTO THE REGION. THE COOLER TEMPERATURES AND LOWER DEW
POINTS COULD BRING THE POTENTIAL FOR FROST TO THE REGION ON MONDAY
AND TUESDAY MORNINGS.

THURSDAY THROUGH SATURDAY THE GEM...GFS...AND ECMWF BEGIN TO
STRONGLY AMPLIFY THE 500 HPA PATTERN OVER THE THE LOWER 48 WITH DEEP
TROUGHING ALONG THE WEST AND EAST COASTS RIDGING BUILDING INTO THE
CENTRAL PLAINS. THIS WILL LEAD TO A GRADUAL WARMING TREND LATE IN
THE WEEK AND CONTINUING INTO NEXT WEEKEND. THIS PATTERN WILL BE
FAIRLY PROGRESSIVE WITH THE GFS AND ECWMF BRING A SHORTWAVE INTO THE
PACIFIC NORTHWEST. THIS WILL WORK TO DAMPEN THE 500 HPA FLOW AND
RIDGE OVER THE THE CENTRAL US. SOME DIFFERENCES IN THE TIMING AND
PLACEMENT OF THIS FEATURE WITH THE ECMWF BEING A LITTLE QUICKER AND
STRONG FEATURE THAN THE GFS. BOTH MODELS PRODUCE SCATTERED SHOWERS
ACROSS MINNESOTA...WISCONSIN...IOWA...AND ILLINOIS. HOWEVER THE
MODEL RH AND CONDENSATION PRESSURE DEFICITS APPEAR TOO DRY TO
PRODUCE ANY RAINFALL AT THIS TIME. IN CONJUNCTION WITH THIS SYSTEM
THE MODELS ALSO DEPICT A LOW MOVING ACROSS THE SOUTHERN U.S. WHICH
MAY LIMIT THE AVAILABLE MOISTURE. TEMPERATURES WILL CONTINUE TO WARM
INTO THE WEEKEND WITH WARM SOUTHERLY FLOW AT THE SURFACE.
TEMPERATURES MAY BE LIMITED BY ANY CLOUDS. PLEASE STAY TUNED TO SEE
HOW THIS SYSTEM EVOLVES.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1235 PM CDT SAT APR 25 2015

IFR TO MVFR CONDITIONS WITH POCKETS OF VFR WILL CONTINUE THROUGH
00Z/26. AFT 00Z/26 CONDITIONS WILL SLOWLY IMPROVE TO VFR AS THE
STORM SYSTEM MOVES UP THE OHIO VALLEY. HOWEVER...THE POSSIBILITY
DOES EXIST FOR SOME PATCHY FOG DEVELOPMENT PRIOR TO SUNRISE WHICH
MAY RESULT IN POCKETS OF IFR/MVFR CONDITIONS.


&&

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

$$

SYNOPSIS...08
SHORT TERM...08
LONG TERM...COUSINS
AVIATION...08



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