Area Forecast Discussion
Issued by NWS Quad Cities, IA IL

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FXUS63 KDVN 262027
AFDDVN

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
327 PM CDT TUE APR 26 2016

.SYNOPSIS...
ISSUED AT 327 PM CDT TUE APR 26 2016

RAIN AND THUNDERSTORMS ASSOCIATED WITH A MCV THAT MOVED ACROSS
CENTRAL MO TODAY LEAD TO THE DEVELOPMENT OF SHOWERS AND
THUNDERSTORMS ACROSS THE CWA. THESE STORMS WERE FOCUSED ALONG A H8
CONVERGENCE AXIS THAT DOVE SOUTH INTO CENTRAL IL. A WEAK WAKE LOW
DEVELOPED BEHIND THE LINE AND LEAD TO WINDS THAT GUSTED TO NEAR 40
MPH AT SOME SITES. NE FLOW OFF LAKE MICHIGAN PUSHED IN A COOLER
THAN EXPECTED DAY WITH LOW CLOUDS. THIS BOUNDARY WAS FORECAST TO
PUSH FURTHER SOUTH TODAY. A TRICKY SHORT TERM FORECAST DRIVEN BY
MESOSCALE FEATURES WAS THE MAIN FORECAST PROBLEM FOR THE SHORT
TERM.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 327 PM CDT TUE APR 26 2016

OVERALL GUIDANCE ON THE SYNOPTIC SCALE SIDE SUGGESTS THAT THE A
WEAKENING MIDLAT CYCLONE WILL BE OCCURRING ACROSS THE AREA THROUGH
THE PERIOD. AN OCCLUDED SFC LOW WILL TRACK TO THE WEST OF THE AREA
WITH THE MAIN WARM SECTOR ACROSS SW IA AND NORTHERN MO. THESE
MODELS SUGGEST ROBUST PRECIP ALONG A WARM ADVECTION WING LATER
TOMORROW AS THE LOW LUMBERS TO THE EAST. CONCEPTUALLY THIS MAKES
SENSE WITH THE SE FLOW OFF LAKE MICHIGAN AND WEAK FLOW OPPOSING
ANY MOVEMENT NORTH OF THE WARM SECTOR INTO THE CWA. HOWEVER...WHAT
MOST OF THESE MODELS DID NOT HAVE WAS THE PRECIP THAT OCCURRED
TODAY ACROSS THE AREA. I HAVE LOW CONFIDENCE IN THE FORECAST
TOMORROW. I WILL GIVE A COUPLE OF SOLUTIONS THAT I SEE POSSIBLE.

1. OVERALL SYNOPTIC MODELS ARE CORRECT AND THE WARM SECTOR STAYS
SOUTH OF US. I FAVORED THIS IDEA AS LAKE MICHIGAN USUALLY HAS A
STRONG SWAY ON THE SOLUTION DURING PERIODS LIKE THIS AND THE
SYNOPTIC MODELS ARE USUALLY OVERDONE ON NORTHERN EXTEND OF THE
WARM SECTOR. AS SUCH I HAVE MOSTLY RAIN WITH SOME THUNDER ACROSS
THE SOUTH AS A WARM ADVECTION WING MOVES NORTH.
2. CAMS ARE CORRECT WITH A WARM ADVECTION WING THAT FAVORS LITTLE
PRECIP OVERNIGHT AND INTO TOMORROW. THE RAIN THAT OCCURRED TODAY
ACTS TO LIMIT THE REACH OF LAKE MICHIGANS DENSITY CURRENT AND
SUBSEQUENTLY HAS A WARM SECTOR THAT IS ACROSS THE SOUTHERN 1/3RD
OF THE CWA. IN THIS SITUATION...STRONG TO EVEN A SEVERE
THUNDERSTORM MAY BE POSSIBLE TOMORROW. CAM MODELS HAVE
REDEVELOPMENT IN THE AFTERNOON ALONG THE OCCLUDED FRONT TRIPLE
POINT WITH THE LAKE BOUNDARY. A SITUATION LIKE THIS...ESPECIALLY
WITH ANY INSTABILITY...COULD LEAD TO STORMS ACROSS THE AREA. AT
THIS TIME...MY CONFIDENCE IS LOW IN THIS POSSIBILITY...HOWEVER I
FEEL IT PERTINENT TO MENTION.

REGARDLESS THE FORECAST TODAY WAS DIFFICULT DUE TO MESOSCALE
FEATURES AND THE FORECAST TOMORROW WILL BE DIFFICULT FOR THE SAME
REASON. THE DAY 2 SPC OUTLOOK SHIFTED SLIGHTLY NORTH...A NOD TO
THE CAMS. AT THIS POINT I DO NOT HAVE HIGHER CONFIDENCE TO FOLLOW
THAT SOLUTION AS THE STORMS TO THE WEST WILL AFFECT US TOMORROW.


.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 327 PM CDT TUE APR 26 2016

CONTINUED ACTIVE WEATHER WITH MAINLY BELOW NORMAL HIGH TEMPERATURES
ARE THE HIGHLIGHTS OF THE LONG TERM FORECAST PERIOD.

WEDNESDAY EVENING...ISOLATED STRONG TO SEVERE STORMS MAY BE ONGOING
ACROSS THE SOUTHERN COUNTIES NEAR THE NORTHWARD ARCING FRONT. EXPECT
A DECREASE IN COVERAGE OF SHOWERS/ISOLATED STORMS AFTER MIDNIGHT.

ON THURSDAY...THE MAIN UPPER TROUGH WILL PUSH EAST ACROSS THE
REGION...WITH THE HIGHEST COVERAGE OF RAIN NORTH OF INTERSTATE 80.
NORTHEAST FLOW NORTH OF THE BOUNDARY SHOULD PROVIDE A QUITE CHILLY
DAY ALONG AND NORTH OF INTERSTATE 80...WITH HIGHS IN THE 50S.

FRIDAY...UPPER RIDGING WILL MOVE THROUGH THE REGION WITH DRY
CONDITIONS AND BELOW NORMAL HIGHS IN THE 60S. UPPER FLOW WILL
TRANSITION TO SOUTHWESTERLY FRIDAY NIGHT INTO SATURDAY WITH
WIDESPREAD SHOWERS AND EMBEDDED THUNDERSTORMS DEVELOPING. MODERATE
TO ISOLATED HEAVY RAINFALL AMOUNTS ARE LIKELY...WITH AN OVERALL LOW
THREAT OF SEVERE STORMS. SHOWERS WILL LINGER SUNDAY BEFORE THE
SYSTEM HEADS EAST FOLLOWED BY MAINLY DRY WEATHER FOR THE FIRST PART
OF NEXT WEEK. HIGH TEMPS SATURDAY INTO EARLY NEXT WEEK WILL BE
MAINLY IN THE 50S AND 60S...WITH LOWS IN THE 40S.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1247 PM CDT TUE APR 26 2016

DIFFICULT AVIATION FORECAST THROUGH THE PERIOD AS THUNDERSTORMS
AND LOW CLOUDS ARE AFFECTING THE TAF SITES IN THE SHORT TERM AND
THEN ANOTHER ROUND OF THUNDER AND LOW CIGS IN THE AM TOMORROW.
LOOKS LIKE THE IFR AND NOW MVFR DECK THAT MOVED IN FROM THE NORTH
STOPPED A FEW MILES FROM MLI. CONVECTION SHOULD KEEP AREAS SOUTH
IN VFR FLIGHT RULES. LATER TODAY WINDS SHOULD INCREASE AND MVFR
CIGS SHOULD REDEVELOP AS A WARM FRONT TRIES TO MOVE NORTH EARLY
TOMORROW. ALL SITES WITH THE EXCEPTION OF DBQ HAVE A CHANCE FOR
THUNDER...HOWEVER AT THIS TIME WITH LOW CONFIDENCE ON TIMING HAVE
GONE WITH PROB30 AT THOSE SITES.


&&

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

$$

SYNOPSIS...GIBBS
SHORT TERM...GIBBS
LONG TERM...RP KINNEY
AVIATION...GIBBS


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