461
FXUS63 KDVN 240522
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1222 AM CDT THU SEP 24 2026
..06Z AVIATION UPDATE
KEY MESSAGES
- ISOLATED SPRINKLES/DRIZZLE FOR MUCH OF THE SECOND HALF OF THE
WORK WEEK. THE WET PATTERN LOOKS TO RE-ESTABLISH ITSELF
STARTING THIS WEEKEND AND INTO NEXT WEEK WITH MOISTURE FROM
TROPICAL SYSTEMS.
- TEMPERATURES WILL CONTINUE THE COOLER THAN NORMAL TREND TO END
THE MONTH AND START OCTOBER.
SHORT TERM /THROUGH FRIDAY/
ISSUED AT 147 PM CDT WED SEP 23 2026
PERSISTENT LOW LEVEL EASTERLY FLOW COMBINED WITH THE NOR'EASTER ON
THE EAST COAST WILL PUSH MOISTURE WESTWARD INTO THE AREA THROUGH
THURSDAY NIGHT. PROGGED SOUNDINGS OF THE ATMOSPHERE SHOW THIS
MOISTURE TO BE FAIRLY SHALLOW SO NOT MUCH IN THE WAY OF
PRECIPITATION IS EXPECTED.
HOWEVER A WEAK UPPER LEVEL DISTURBANCE MOVING THROUGH THE AREA THIS
AFTERNOON HAS MANAGED TO PRODUCE SOME SPRINKLES/DRIZZLE. ANOTHER
WEAK DISTURBANCE APPROACHING FROM THE PLAINS THURSDAY AFTERNOON AND
NIGHT LOOKS TO PROVIDE THE SAME SET-UP; SCATTERED SPRINKLES AND
PATCHY DRIZZLE.
OTHERWISE, IT WILL BE A MIX OF CLOUDS AND SUN THE NEXT 42 HOURS WITH
COOLER THAN NORMAL TEMPERATURES. THE CU RULE DOES HAVE A DIURNAL
TREND TO THE CLOUDS BUT WITH STEEP LOW LEVEL LAPSE RATES EVEN AT
NIGHT, SOME CLOUD COVER WILL PERSIST AFTER SUNSET.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
ISSUED AT 147 PM CDT WED SEP 23 2026
FRIDAY THROUGH WEDNESDAY
ASSESSMENT...HIGH (>80%) CONFIDENCE ON COOLER THAN NORMAL
TEMPERATURES.
A SLIGHTLY STRONGER UPPER LEVEL DISTURBANCE WILL ARRIVE IN THE
FRIDAY/SATURDAY TIME FRAME BRINGING A RISK FOR RAIN. HOWEVER, THE
SYSTEM WILL BE FIGHTING RELATIVELY DRY EASTERLY FLOW AHEAD OF IT.
ADD TO THIS A SURFACE BASED REX BLOCK FROM THE STRONG CANADIAN HIGH
AND THE NOR'EASTER ON THE EAST COAST SHOULD RESULT IN A SLOWER
ARRIVAL OF THE SYSTEM.
INDEED TRENDS WITH THE GLOBAL MODELS DO APPEAR TO SUGGEST A SLIGHTLY
NEGATIVE DELTA ON THE RAIN CHANCES FOR FRIDAY. THUS THE FRIDAY DAYLIGHT
HOURS AND POTENTIALLY EVENING HOURS MAY END UP BEING MAINLY DRY
FOR MOST OF THE AREA. THE BETTER TIMING FOR ANY RAIN APPEARS TO
BE SATURDAY INTO SATURDAY NIGHT AS THE CANADIAN HIGH MOVES
FURTHER EAST AND THE BETTER FORCING FROM THE SYSTEM ARRIVES.
UNLIKE LAST WEEK, RAINFALL AMOUNTS FOR THIS EVENT WILL BE ON THE
LIGHT SIDE.
THE NEXT CHANCE FOR RAIN IS STARTING TO CENTER AROUND
TUESDAY/WEDNESDAY OF NEXT WEEK. DURING THIS TIME FRAME THE MODELS
ARE SHOWING A STRONG TROPICAL CONNECTION TO THE SYSTEMS IN THE
EASTERN PACIFIC UP INTO THE MIDWEST. THE MODEL CONSENSUS ALREADY HAS
A MEDIUM TO HIGH (50-70%) PROBABILITY OF RAIN OCCURRING DURING
THIS TIME FRAME. PWATS OF 1.5 TO 2 INCHES ARE ALREADY BEING
PROGGED BY THE GLOBAL MODELS INDICATING A HIGH (>80%)
PROBABILITY OF HEAVY RAIN OCCURRING.
ALTHOUGH BEYOND THE SCOPE OF THE 7 DAY FORECAST, THE HIGH PWATS LOOK
TO RELOAD AGAIN LATE NEXT WEEK FOR THE NEXT SYSTEM. THIS SIGNAL
WOULD BE CONSISTENT THE WITH MJO VACILLATING BETWEEN PHASES 8 AND 1
WHICH CORRELATES TO ABOVE NORMAL PRECIPITATION FOR THE AREA.
AVIATION /06Z TAFS THROUGH 06Z FRIDAY/
ISSUED AT 1215 AM CDT THU SEP 24 2026
LLVL EASTERLY FLOW IN A BLOCKED WEATHER PATTERN WILL CONTINUE
TO ADVECT A SUBSTANTIAL STRATOCU DECK IN FROM THE EAST OVERNIGHT
AND INTO THURSDAY. MOST OF THIS DECK HELD UNDER A H85-H75 MB
INVERSION AND SHOULD BE MAINLY AT VFR LEVELS, BUT THERE MAY BE
BASE LOWERING AT TIMES BELOW 3K FT AGL ESPECIALLY SOUTH OF I-80
THROUGH EARLY THU AFTERNOON. SFC WINDS REMAIN A CONSTANT
GENERALLY EAST TO NORTHEAST AT 7-12 KTS THROUGH THE PERIOD.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...08
LONG TERM...08
AVIATION...12
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