096
FXUS63 KDVN 141139
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
639 AM CDT FRI AUG 14 2020
..AVIATION UPDATE
SYNOPSIS
ISSUED AT 300 AM CDT FRI AUG 14 2020
HIGH PRESSURE WAS IN CONTROL OVER THE GREAT LAKES INTO PORTIONS OF
THE MID TO UPPER MISSISSIPPI VALLEY. AS OF 3 AM, TEMPERATURES
ACROSS EASTERN IOWA AND NORTHWEST ILLINOIS WERE IN THE 60S TO
LOWER 70S. THE COOL SPOT WAS FREEPORT AT 60 F AND THE WARMEST
LOCATION WAS BURLINGTON AT 73 F.
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 300 AM CDT FRI AUG 14 2020
ANOTHER VERY WARM DAY IS ON TAP WITH HIGHS IN THE MID TO UPPER
80S EXPECTED FOR MOST OF THE FORECAST AREA. LIGHT ESE TO SE WINDS
SHOULD ADVECT IN SLIGHTLY LESS HUMID AIR COMPARED TO YESTERDAY,
WITH DEWPOINTS IN THE LOW TO MID 60S EAST AND UPPER 60S WEST.
CONVECTION IS EXPECTED TO DEVELOP THIS AFTERNOON ALONG A COLD
FRONT DRAPED ACROSS SOUTHWEST MINNESOTA AND NORTHWEST IOWA. THIS
ACTIVITY WILL TRACK TO THE SE INTO TONIGHT, FOLLOWING THE
850-300MB STEERING FLOW ALOFT. INSTABILITY AND FORCING WILL
CONTINUE TO WANE OVERNIGHT WITH HREF MUCAPE DROPPING INTO THE
1000-1500 J/KG RANGE ALONG AND WEST OF THE MISSISSIPPI RIVER.
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE LOCALLY, MAINLY
AFTER MIDNIGHT WITH THE BEST CHANCES (30-50%) ACROSS THE WEST AND
NORTHWEST FORECAST AREA. CHANCES THEN TAPER OFF TO 20% AROUND THE
QUAD CITIES FOR VERY LATE TONIGHT INTO EARLY SATURDAY MORNING.
COVERAGE OF THE RAIN WILL LIKELY REMAIN SCATTERED AT BEST. THEREFORE,
IT DOES NOT APPEAR THIS WILL BE THE WIDESPREAD SOAKING RAIN THAT
IS NEEDED ACROSS MUCH OF THE REGION, WHICH HAS BEEN ABNORMALLY
DRY THE PAST SEVERAL WEEKS. UTTECH
LONG TERM
(SATURDAY THROUGH THURSDAY)
ISSUED AT 300 AM CDT FRI AUG 14 2020
THE MODELS ARE IN GOOD AGREEMENT THROUGH THE PERIOD. THE MAIN
FORECAST CONCERNS WERE CHANCES OF PRECIPITATION THROUGH THE PERIOD.
A COLD FRONT WILL BE APPROACHING THE MISSISSIPPI RIVER BY 12 UTC ON
SATURDAY WHEN THE LONG TERM FORECAST PERIOD BEGINS. AT 500 MB, A
SHORTWAVE TROUGH AND A 250 MB JET STREAK ARE FORECAST TO DIG INTO
MINNESOTA AND WISCONSIN DURING THE DAY ON SATURDAY AND QUICKLY DRIVE
THE PREVIOUSLY MENTIONED COLD FRONT ACROSS NORTHWEST ILLINOIS. THE
BETTER FORCING IS TO OUR NORTH AND CONVERGENCE ALONG THE FRONT IS
FORECAST TO BE WEAK WITH A BRIEF WINDOW OF SCATTERED SHOWERS AND
THUNDERSTORMS ALONG THE FRONT. INSTABILITY WILL BE LIMITED GIVEN THE
TIME OF DAY AND THE SHEAR WILL BE WEAK ACROSS THE AREA SO THE THREAT
FOR SEVERE STORMS APPEARS TO BE LOW.
IN THE WAKE OF SATURDAYS STORMS SYSTEM AND COLD FRONT, COOLER AND
LESS HUMID AIR WILL MOVE INTO THE REGION AND REMAIN THERE THROUGH
THE REMAINDER OF THE PERIOD. THE TROUGH DIGGING INTO THE EASTERN US
AND A RIDGING BUILDING ACROSS THE WESTERN US WILL RESULT IN
NORTHWESTERLY FLOW ALOFT ACROSS EASTERN IOWA, NORTHWEST ILLINOIS AND
FAR NORTHEAST MISSOURI. THE JET STREAM WILL BE WELL NORTH OF THE
AREA THROUGH THE PERIOD. HOWEVER MODELS DO DEPICT SEVERAL SHORTWAVES
MOVING THROUGH THE NORTHWESTERLY FLOW THROUGH THE PERIOD. MOISTURE
WILL BE LIMITED AND THESE PASSING SHORTWAVES WILL LIKELY RESULT IN
CLOUD COVER AND NOT RAIN. AFTER NEAR NORMAL TEMPERATUES ON SATURDAY
SUNDAY, EXPECT NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH
THE REMAINDER OF THE WEEK. NORMAL HIGH TEMPERATURES FOR THE MIDDLE
THIRD OF AUGUST RANGE FROM 80 TO 85 DEGREES FROM NORTH TO SOUTH
ACROSS THE AREA WITH NORMAL LOW TEMPERATURES AROUND 60 TO 64
DEGREES. DEWPOINTS WILL BE IN A COMFORTABLE MID TO UPPER 50S.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 630 AM CDT FRI AUG 14 2020
HIGH PRESSURE IS MOVING ACROSS THE AREA THIS MORNING WITH VFR
CEILINGS AND VISIBILITIES ACROSS THE AREA. SOME AVIATION FOG THIS
MORNING WITH VISIBILITIES BETWEEN 3 AND 5 MILES. CONDITIONS WILL
IMPROVE THROUGH 15 UTC.
A COLD FRONT IS FORECAST TO MOVE THROUGH EASTERN IOWA TAF SITES
TONIGHT WITH WINDS REMAINING LIGHT BUT SWITCHING TO THE NORTHWEST
BEHIND THE FRONT. CEILINGS WILL REMAIN VFR THROUGH THE PERIOD.
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG THE FRONT
BUT CONFIDENCE IS LOW THAT THEY WILL IMPACT ANY ONE LOCATION.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SYNOPSIS...UTTECH
SHORT TERM...UTTECH
LONG TERM...COUSINS
AVIATION...COUSINS
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