264
FXUS63 KDVN 082317
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
617 PM CDT THU OCT 8 2026
KEY MESSAGES
- SHOWERS/STORMS MOVING IN LATE TONIGHT INTO FRIDAY AM, BRINGING
LIGHT RAINFALL FOR MANY. THERE WILL BE A LOW-END THREAT FOR
STRONG/SEVERE STORMS, WITH HAIL BEING THE PRIMARY THREAT.
- A DRY AND UNSEASONABLY MILD WEEKEND IS AHEAD OF US, FEATURING
MOSTLY CLEAR SKIES AND LIGHT WINDS.
- PRECIPITATION CHANCES WILL BE ON THE RISE MID-LATE NEXT WEEK.
SHORT TERM /THROUGH FRIDAY/
ISSUED AT 202 PM CDT THU OCT 8 2026
SURFACE HIGH PRESSURE WILL TRACK EAST OF THE AREA THROUGH THIS
EVENING, WHICH WILL LEAD TO A CONTINUATION OF QUIET AND DRY WEATHER
PRIOR TO MIDNIGHT. WE WILL LARGELY SEE AN INCREASE IN CLOUDS AS THIS
MOVES OUT AND THE NEXT SYSTEM APPROACHES THE AREA, WITH LLVL WINDS
BECOMING MORE SOUTHWESTERLY. UPPER LEVEL NORTHWEST FLOW WILL REMAIN
OVERHEAD THROUGH THE END OF THE WORK WEEK, WITH A SUBTLE SHORTWAVE
PASSING THROUGH THE AREA TONIGHT INTO FRIDAY AM. BEST FORCING WILL
MOVE IN TONIGHT AFTER MIDNIGHT, WITH THE LLJ INCREASING OUT OF THE
SOUTHWEST AROUND THE SAME TIME. WE WILL CONTINUE TO SEE THE LLJ
INCREASE THROUGH FRIDAY MORNING, SUPPLYING THE NECESSARY MOISTURE TO
SEE SCATTERED SHOWERS AND STORMS. OVERNIGHT PRECIPITATION CHANCES
WILL BE AROUND 20-40%, FOCUSED NEAR THE INTERSTATE 80 CORRIDOR PRIOR
TO SUNRISE. ALTHOUGH, THERE REMAINS SOME UNCERTAINTY ON
PRECIPITATION TIMING. SOME CAMS DON'T INITIATE ANY SHOWERS/STORMS
UNTIL THE FRIDAY AM COMMUTE, WHILE SOME INITIATE CLOSER TO MIDNIGHT
TONIGHT. THIS UNCERTAINTY STEMS FROM MOISTURE AVAILABILITY AND HOW
QUICKLY THE ATMOSPHERE SATURATES. A LOOK AT MODEL SOUNDINGS
INDICATES QUITE A BIT OF LLVL DRY AIR, WHICH WILL TAKE SOME TIME TO
OVERCOME. THUS, THE CURRENT THOUGHT IS THAT BETTER CHANCES FOR
PRECIPITATION WILL BE LATER TONIGHT AND THROUGH FRIDAY MORNING, BUT
ISOLATED CONVECTION CANNOT BE RULED OUT AS EARLY AS MIDNIGHT.
OVERALL, THE BEST COMBINATION FOR FORCING/MOISTURE WILL BE NORTH OF
THE HIGHWAY 34 CORRIDOR, WITH INTERSTATE 80 AND NORTH SEEING THE
BEST PRECIPITATION CHANCES THROUGH FRIDAY AM (30-60% CHANCES).
SPC HAS HIGHLIGHTED OUR FAR WEST, AREAS WEST OF CEDAR RAPIDS, IN A
MARGINAL RISK (LEVEL 1/5) FOR SEVERE WEATHER TONIGHT. OVERALL, THE
MAIN ENVIRONMENTAL PARAMETERS THAT WOULD FAVOR STRONGER TO SEVERE
STORMS WOULD BE DEEP LAYER SHEAR AND MIDLEVEL LAPSE RATES, WHICH
WOULD SUPPORT SOME ORGANIZED CONVECTION. ALTHOUGH, MUCH OF GUIDANCE
KEEPS INSTABILITY AROUND 500 CAPE OR LESS, WITH SOME OF THE MORE
AGGRESSIVE CAMS HAVING BETWEEN 500-1000 J/KG (LOWER CONFIDENCE). IF
WE MANAGE TO GET A STRONG/SEVERE STORM, MAIN HAZARD WILL BE HAIL.
PRECIPITATION ACCUMULATION SHOULD BE LOWER, ROUGHLY BETWEEN 0.10-
0.25" FOR AREAS NORTH OF HIGHWAY 34, WITH THE BEST CHANCE TO SEE
RAINFALL UPWARDS TO 0.50" (30-50% PROBABILITY) CLOSER TO THE
INTERSTATE 80 CORRIDOR AND AREAS NORTH. ALTHOUGH, THERE REMAINS MUCH
UNCERTAINTY DUE TO THE AFOREMENTIONED DRY AIR, LEAVING THOSE HIGHER
AMOUNTS QUITE LOCALIZED. THE NAM IS THE MOST AGGRESSIVE WITH
PRECIPITATION CHANCES TONIGHT, BUT ALSO HAS MUCH HIGHER MOISTURE
THAN MOST OTHER GUIDANCE. THUS, OUR CONFIDENCE IN THAT SOLUTION IS
LOW.
BY MID-LATE AFTERNOON ON FRIDAY, SHOWER/STORM ACTIVITY SHOULD HAVE
LARGELY MOVED OFF NORTHEAST OF OUR AREA, LEAVING US DRY FOR THE
REMAINDER OF THE DAY AND OVERNIGHT. WE WILL ALSO SEE CLOUD COVER
DECREASE QUICKLY THROUGH THE AFTERNOON AS WELL, LEAVING US MOSTLY
CLEAR. TEMPERATURES TOMORROW WILL INCREASE INTO THE MID-UPPER 70S
FOR MANY, ESPECIALLY ALONG/SOUTH OF INTERSTATE 80. AREAS ALONG/SOUTH
OF HIGHWAY 34 ARE EXPECTED TO REACH THE LOW 80S! THUS, UNSEASONABLY
MILD CONDITIONS WILL CLOSE THE WEEK, WITH TEMPERATURES DROPPING INTO
THE LOW 60S FRIDAY NIGHT.
LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/
ISSUED AT 202 PM CDT THU OCT 8 2026
THIS WEEKEND...
A BEAUTIFUL WEEKEND IS AHEAD OF US. WARM FRONT WILL HAVE FULLY MOVED
NORTHEAST AND OUT OF THE AREA, LEAVING US UNDER DECENT WARM
ADVECTION THROUGH THE WEEKEND. AS SUCH, TEMPERATURES ARE EXPECTED TO
INCREASE WELL ABOVE SEASONAL NORMALS, ESPECIALLY SATURDAY WITH THE
STRONGEST WARM ADVECTION. WIDESPREAD TEMPERATURES IN THE LOW 80S ARE
EXPECTED SATURDAY, WITH MID-UPPER 70S SUNDAY. MOSTLY CLEAR
CONDITIONS WILL ALSO PREVAIL, WITH SOME PASSING HIGH CLOUDS ON
SUNDAY ASSOCIATED WITH CIRRUS FROM ISAIAS POST-LANDFALL.
NEXT WEEK...
ZONAL FLOW WILL START THE NEW WORK WEEK, WITH LLVL FLOW INCREASING
OUT OF THE SOUTHWEST AHEAD OF A PASSING WEAK SHORTWAVE. MONDAY WILL
REMAIN DRY AND UNSEASONABLY MILD, WITH THE WAVE AND ASSOCIATED COLD
FRONT PASSING THROUGH MONDAY NIGHT INTO TUESDAY. MOISTURE WILL
REMAIN LIMITED AHEAD OF THE FRONT, WHICH SHOULD LIMIT
PRECIPITATION CHANCES FOR MOST (<15% CHANCES). THUS, A LARGELY
DRY FORECAST. AFTER THAT WAVE, WE WILL SEE BRIEF RIDGING PRIOR
TO A STRONG WAVE DEEPENING OVER THE ROCKIES. AS THIS DEEPENS,
SOUTHWEST FLOW WILL SET UP OVER THE CENTRAL CONUS, SHUNTING THE
RIDGE EAST WEDNESDAY. WARM ADVECTION WILL INCREASE OVERHEAD
THROUGH MIDWEEK, WITH SHORTWAVES PASSING THROUGH AHEAD OF THIS
DEEP WAVE. THUS, A MORE ACTIVE PATTERN WILL TAKE SHAPE AND
CHANCES FOR SHOWERS/STORMS WILL BE ON THE RISE MIDWEEK AND
BEYOND. IT IS TOO SOON TO DETERMINE THE THREAT OF STRONG/SEVERE
STORMS, ALONG WITH HEAVY RAIN POTENTIAL.
AVIATION /00Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 614 PM CDT THU OCT 8 2026
A WEAK WARM FRONT IS SET UP OVER THE AREA THIS EVENING, ALONG
I-80, FROM IOWA THOUGH ILLINOIS. THIS WILL BE THE FOCUS FOR LATE
NIGHT SHOWERS AND THUNDERSTORMS, WHICH WILL INITIALLY BE VERY
HIGH BASED, AND DEVELOP IN CENTRAL AND WESTERN IOWA THROUGH
MIDNIGHT, BEFORE SPREADING EAST IN A NARROW SWATH THROUGH
EASTERN IOWA AND ILLINOIS, MOST ESPECIALLY NEAR INTERSTATE 80.
THIS ROUND OF SHOWERS/STORMS WILL BE QUICKLY MOVING EAST OF THE
AREA NOT LONG AFTER SUNRISE FRIDAY MORNING. THIS WILL RETURN THE
AREA TO DRY WEATHER FOLLOWING THE STORMS EXIT. WINDS WILL BE
GENERALLY LIGHT OVERNIGHT, AND SOUTHEAST AT 5-15 KTS FRIDAY.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...GUNKEL
LONG TERM...GUNKEL
AVIATION...ERVIN
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