578
FXUS63 KDVN 251933
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
233 PM CDT THU APR 25 2024
KEY MESSAGES
- SLGT RISK FOR SEVERE STORMS IN OUR WESTERN COUNTIES FRIDAY.
- BETTER CHANCE FOR SEVERE STORMS SUNDAY AFTERNOON/EVENING.
- MODELS HAVE REDUCED THE RAINFALL AMOUNTS THROUGH THE WEEKEND.
SHORT TERM /THROUGH FRIDAY NIGHT/
ISSUED AT 230 PM CDT THU APR 25 2024
SAY GOODBYE TO THE NICE WEATHER FOR AWHILE AS WE GET INTO AN
ACTIVE PATTERN BEGINNING TONIGHT. DEEP LOW PRESSURE (988 MB)
WILL BE TRACKING FROM EASTERN CO TO EASTERN SD. GFS/NAMNEST/HRRR
HAVE SLOWED THE PROGRESSION OF THE SHOWERS AND THUNDERSTORMS,
AND NOW SHOW THE LEADING EDGE MOVING INTO OUR WESTERN COUNTIES
BY DAWN, AND THEN OUR FAR EASTERN COUNTIES BY NOON FRIDAY.
SHOULD REACH DUBUQUE AND THE QUAD CITIES BY AROUND 9 AM. THIS
ROUND OF SHOWERS AND SCATTERED THUNDERSTORMS WILL BE OCCURING ON
THE NOSE OF A STRENGTHENING LOW LEVEL JET BRINGING A NICE SURGE
OF MOISTURE/WARM AIR ADVECTION. FORECAST SOUNDINGS SUGGEST
THESE STORMS WILL BE ELEVATED BUT MUCAPE IS VERY LIMITED, SO
NOT EXPECTING SEVERE STORMS. SOME OF THE MODELS SHOW A DECREASE
IN THE ACTIVITY IN THE AFTERNOON, THEN SOME RE-DEVELOPMENT
POSSIBLE LATER IN THE AFTERNOON AND EVENING. THE BULK OF THE
SEVERE STORMS SHOULD REMAIN ACROSS WESTERN/CENTRAL IOWA THEN AN
ARC OF STORMS MAY ENTER OUR NORTHWEST COUNTIES OVERNIGHT ON
FRIDAY NIGHT, BUT IN A WEAKENING FASHION. STRONG GRADIENT
SOUTHEAST WINDS WILL BE GUSTING TO AROUND 35 MPH.
LOWS TONIGHT IN THE 40S WITH HIGHS ON FRIDAY RANGING FROM THE
MID 50S NORTH TO THE MID 60S SOUTH. LOWS FRIDAY NIGHT IN THE
LOWER 50S NORTH TO THE LOWER 60S SOUTH.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
ISSUED AT 230 PM CDT THU APR 25 2024
SATURDAY THROUGH SUNDAY NIGHT: GLOBAL MODELS HAVE REALLY BACKED
OFF ON PCPN FOR SATURDAY. CAN'T RULE OUT SOME ISOLATED SHOWERS
AND STORMS BUT NOT MUCH IN THE WAY OF FORCING. WE WILL BE
BETWEEN STORM SYSTEMS, AS THE FIRST CYCLONE PUSHES TO THE
NORTHERN GREAT LAKES REGION, WHILE ANOTHER STRONG CYCLONE
ORGANIZES OFF THE LEE OF THE ROCKIES IN EASTERN CO. THIS SECOND
STORM SYSTEM WILL RETURN STRONG FORCING AND WITH A FRONTAL
BOUNDARY DRAPED SOUTHWEST-NORTHEAST ACROSS THE FORECAST AREA,
NUMEROUS SHOWERS AND THUNDERSTORM SHOULD OCCUR SATURDAY NIGHT
INTO SUNDAY MORNING. HEAVY RAINFALL IS LIKELY WITH THESE STORMS.
DEPENDING ON HOW LONG THE STORMS LAST ON SUNDAY WILL DETERMINE
THE SEVERE THREAT. ANY BREAK IN THE ACTION TO ALLOW SUNSHINE
WOULD INCREASE THE SEVERE POTENTIAL. SPC CONTINUES THE SLGT RISK
ON SUNDAY AFTERNOON INTO SUNDAY NIGHT. THE PCPN SHOULD DIMINISH
LATER SUNDAY NIGHT AS THE CYCLONE TRACKS TO NEAR THE TWIN CITIES.
HIGHS ON THE WEEKEND WILL BE WELL INTO THE 70S TO LOWER 80S.
RAINFALL AMOUNTS: YESTERDAY THE MODEL QPF TOTAL THROUGH THE
WEEKEND WAS AROUND 3.50 INCHES FOR MUCH OF THE FORECAST AREA.
HOWEVER, THE NEW MODEL DATA THIS MORNING HAS BACKED OFF TO
AMOUNTS OF 2.50 INCHES WEST TO 1.50 INCHES EAST. IS THIS A TREND
THAT WILL CONTINUE OR WILL THE HIGH RAINFALL AMOUNTS RETURN IN
LATER MODELS? TIME WILL TELL.
MONDAY THROUGH WEDNESDAY: ANY LINGERING SHOWERS WILL END IN THE
MORNING ON MONDAY WITH HIGHS IN THE MID 60S TO LOWER 70S. ZONAL
FLOW TUESDAY AND WEDNESDAY MAY ALLOW FOR CHANCES FOR SHOWERS AND
THUNDERSTORMS BUT TIMING THE DISTURBANCES IN THE FLOW IS TRICKY
THIS FAR OUT. HIGHS WILL BE IN THE 70S.
AVIATION /18Z TAFS THROUGH 18Z FRIDAY/
ISSUED AT 1238 PM CDT THU APR 25 2024
VFR CONDS THROUGH TONIGHT THEN DETERIORATING TO IFR CIGS/VIS IN
RAIN FRIDAY MORNING. IN ADDITION, STRENGTHENING WINDS IN THE LOW
LEVELS WILL CREATE LLWS LATE TONIGHT INTO FRIDAY MORNING.
SURFACE WINDS WILL BE SOUTHEAST GUSTING TO AROUND 30 KTS
ESPECIALLY ON FRIDAY.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...HAASE
LONG TERM...HAASE
AVIATION...HAASE
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