395
FXUS63 KDVN 120518
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1218 AM CDT FRI AUG 12 2022
SYNOPSIS
ISSUED AT 246 PM CDT THU AUG 11 2022
THE MAIN SFC FRONT WAS PUSHING ACRS THE FAR SOUTHERN INTO
SOUTHWESTERN CWA ATTM, WHILE ALOFT NORTHWEST FLOW WAS USHERING ACRS
A S/W TROF ACRS EASTERN IA. MOISTURE FEED WITH PWATS OVER 1.5 INCHES
FLOWING UP AROUND THE CENTRAL ROCKIES UPPER RIDGE FEEDING SCTRD TO
ISOLATED SHOWER/STORM ACTIVITY ALONG THE BOUNDARY OR EVEN POST-
FRONTALLY LIKE THE ELEVATED ACTIVITY ACRS NORTHEAST INTO CENTRAL IA
ATTM. POST-FRONTAL TEMPS IN THE 70S TO LOW 80S, WITH MID 80S SOUTH.
SHORT TERM
(THIS EVENING THROUGH FRIDAY)
ISSUED AT 246 PM CDT THU AUG 11 2022
TONIGHT... WILL CARRY LOW TO MODERATE POPS FOR SCTRD TO ISOLATED
SHOWERS AND FEW STORMS SOUTH AND WEST THROUGH MID EVENING NEAR THE
FRONT(SOUTH)AND POST FRONTALLY IN THE WEST. THEN EXPECT A TEMPORARY
LULL OR DECREASE IN PRECIP ACTIVITY BY MID TO LATE EVENING, BEFORE
MORE DEVELOPS ON AN ELEVATED WARM AIR ADVECTION WING/CONVERGENT LLJ
NOSE LATE TONIGHT. ENOUGH CAPE AND SHEAR LATE THIS AFTERNOON TO
SUPPORT A STRONGER STORM LIKE WHAT OCCURRED NORTHEAST OF DES MOINES,
BUT THEY MAY WEAKEN SOME AS THEY TRY TO MAKE IT INTO THE WESTERN
CWA. BUT A HIGHER BASED STORM WITH AT LEAST SMALL HAIL STILL MAY BE
POSSIBLE IN THE WEST THIS EVENING. AN ISOLATED STORM POSSIBLE IN THE
SOUTH, BUT SHOULD THEN DRIFT SOUTHWARD INTO CENTRAL IL. WITH THE
HIGH PWATS, SOME PASSING HEAVY DOWNPOURS POSSIBLE AS WELL FROM THE
HEAVIER CELLS. WILL THEN RE-FLARE UP POPS LATE TONIGHT FROM WEST TO
EAST INTO FRIDAY MORNING WITH THE CONVERGENT LLJ NOSE. SMALL HAIL,
LIGHTNING AND PASSING/LOCALIZED HEAVY DOWNPOURS POSSIBLE AGAIN WITH
THE MORE ROBUST CONVECTION. LOW TEMP GRADIENT FROM THE LOWER 50S IN
THE NORTHEAST CLOSER TO SFC RIDGE AXIS, TO THE MID 60S IN THE FAR
SOUTHWEST.
FRIDAY...WILL CONTINUE TO WALK ACRS THE MAINLY ELEVATED BAND OF
SHOWERS AND SOME STORMS FROM WEST TO EAST, AND MAINLY OUT OF THE
AREA BY EARLY AFTERNOON. A QUARTER INCH OF RAINFALL POSSIBLE IN A FEW
SWATHS NORTH OF I80. CLOUD COVER AND POST-FRONTAL COOLING TO KEEP A
LID ON THE HIGH TEMP POTENTIAL WITH MANY AREAS STAYING IN THE LOW TO
MID 70S. THE WEST AND SOUTHWEST WILL STILL WARM UP TO AROUND 80.
LONG TERM
(FRIDAY NIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 246 PM CDT THU AUG 11 2022
[KEY MESSAGES]
1) MAINLY DRY CONDITIONS WITH ONLY PERIODIC SLIGHT CHANCES FOR
PRECIPITATION
2) ABOVE NORMAL TEMPERATURES THIS WEEKEND COOL TO NEAR TO BELOW
NORMAL TEMPERATURES NEXT WEEK
[DISCUSSION]
SURFACE AND LOW-LEVEL LOW PRESSURE WILL BE IN PLACE SOMEWHERE NEAR
THE IA/MN BORDER TO START THE PERIOD, WITH MUCH OF EASTERN IA,
NORTHWEST IL AND FAR NORTHEAST MO UNDERNEATH A ROBUST SURGE OF WAA
AND MOISTURE TRANSPORT. BEARING THIS IN MIND, EXPECTING QUITE A
BIT OF CLOUD COVER TO BE IN PLACE FRIDAY NIGHT THROUGH MUCH OF
SATURDAY, BEFORE THE LOW EVENTUALLY GETS SHUNTED SOUTH OF THE AREA
SATURDAY NIGHT. WHILE I CAN'T RULE OUT AN ISOLATED SHOWER OR
STORM, EXPECTING MOSTLY DRY WEATHER FOR THE AREA AS THE PRIMARY
LIFT ZONE REMAINS WELL INTO NORTHERN IL AND WI.
THE MAIN CHALLENGE FOR SATURDAY WILL BE HOW WARM WE GET GIVEN THE
CLOUD COVER. GUIDANCE CONTINUES TO ADVERTISE TEMPERATURES RANGING
FROM THE LOW 80S IN NORTH CENTRAL IL TO LOW 90S IN SOUTHEAST IA AND
NORTHEAST MO, WITH THE LATER BEING MUCH CLOSER TO THERMAL RIDGING
BUILDING INTO THE AREA. GIVEN THE ROBUST WAA AND SURFACE WINDS FROM
THE SOUTH GUSTING AROUND 20-25 MPH, THINK THERE IS A GOOD CHANCE
THIS WILL BE REALIZED.
COLD FRONT WILL PUSH THROUGH THE AREA SUNDAY MORNING, WITH RELIEF
COMING ON THE TEMPERATURE AND HUMIDITY FRONT WITH HIGH PRESSURE
BUILDING OVER THE GREAT LAKES. TEMPERATURES WILL TURN NEAR TO BELOW
NORMAL FROM THIS AS WE HEAD INTO THE UPCOMING WORK WEEK, WITH DAILY
HIGHS IN THE UPPER 70S TO LOW 80S, AND OVERNIGHT LOWS IN THE UPPER
50S TO LOW 60S THROUGH THURSDAY. DESPITE SOME SLIGHT CHANCES OF
PRECIPITATION MAINLY IN EASTERN IOWA DUE TO PASSING SHORTWAVES IN
NORTHWEST FLOW ALOFT, VERY DRY AIR IN THE LOW-LEVELS FROM THE GREAT
LAKES HIGH WILL PRECLUDE MUCH OF ANY DEVELOPMENT, KEEPING MUCH OF
THE THREAT FURTHER INTO CENTRAL IOWA AND MISSOURI.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1214 AM CDT FRI AUG 12 2022
VFR CONDITIONS WILL PERSIST THROUGH MOST OF THE NEXT 24 HOURS, AS
WE SEE HIGH BASED SHOWERS AND A FEW THUNDERSTORMS MOVE THROUGH
AREAS MAINLY TO THE NORTH OF EASTERN IOWA. SOME STORMS MAY FORM IN
A NARROW AXIS AS FAR SOUTHWEST AS NEAR CID, AND I'VE RETAINED A
TEMPO FOR HIGH BASED THUNDER THERE IN THE 13 TO 16Z TIME FRAME,
BUT IN OTHER SIGHTS, A BIT FARTHER EAST AND SOUTH, WE'RE STAYING
MAINLY DRY AND VFR THROUGH THE PERIOD. CLOUD BASED WILL MAINLY BE
ABOVE 5000 FT, BUT IN ANY SHOWER THEY COULD LOWER TO AROUND 3500
FT FOR A BRIEF PERIOD. AFTER 16Z, DRY, VFR WEATHER WILL BE
WIDESPREAD, WITH WINDS BECOMING SOUTHEAST AROUND 7 TO 10 KTS.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...12
LONG TERM....SPECK
AVIATION...ERVIN
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