248
FXUS63 KDVN 261749
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1249 PM CDT SUN JUL 26 2026
KEY MESSAGES
- OPPRESSIVELY HUMID THROUGH MONDAY EVENING, WITH THE HOTTEST
LOCATIONS UNDER AN EXTREME HEAT WARNING WHERE HEAT INDICES ARE
EXPECTED TO PEAK OVER 105 DURING THESE TWO AFTERNOONS, EVEN
POTENTIALLY OVER 110.
- SCATTERED THUNDERSTORMS IN THE REGION THROUGH MONDAY, SOME
POTENTIALLY ORGANIZED ESPECIALLY LATE TONIGHT AND MONDAY
MORNING IN NORTHWEST ILLINOIS. THESE COULD BE SEVERE WITH
DAMAGING WINDS (LEVEL 2 OF 5 RISK).
SHORT TERM /THROUGH MONDAY/
ISSUED AT 235 AM CDT SUN JUL 26 2026
RADAR IMAGERY EARLY THIS MORNING SHOWS AREAS OF DECAYING CONVECTION
UPSTREAM ACROSS NORTHERN IOWA, SOUTHERN MINNESOTA, AND EASTERN SOUTH
DAKOTA. THIS WILL MOVE INTO EASTERN IOWA OVER THE NEXT SEVERAL
HOURS, BRINGING LOW CHANCES (10-30%) FOR RAIN THROUGH THE EARLY
MORNING. HOW LONG THESE CLOUDS LINGER INTO MID-MORNING COULD HELP
LIMIT TEMPERATURES LATER TODAY, THOUGH IT IS LIKELY (60-80%) THAT
LOW CLOUDS WILL CLEAR OUT AND ALLOW FOR DIURNAL HEATING. THIS WILL
SUPPORT ANOTHER DAY OF INCREASING HEAT AND HUMIDITY, WITH
TEMPERATURES RISING INTO THE LOW TO MID 90S AND HEAT INDICES FROM
100 TO NEAR 110 DEGREES. A HEAT ADVISORY FOR NORTHWEST ILLINOIS AND
AN EXTREME HEAT WARNING FOR THE REMAINDER OF THE AREA REMAIN IN
EFFECT FOR THIS AFTERNOON.
AS WE LOOK TOWARDS SUNDAY NIGHT, THE QUESTION TURNS FROM HEAT
HEADLINES TO STORM POTENTIAL AS A SHORTWAVE MOVES THROUGH LATE
SUNDAY NIGHT INTO MONDAY MORNING. WHILE A COMBINATION OF CAPPING AND
LIMITED FORCING WILL KEEP ANY CONVECTION LIMITED TO NON-EXISTENT
DURING THE DAY IN OUR AREA, STRONGER FORCING UPSTREAM WILL ALLOW FOR
CONVECTION TO DEVELOP UPSTREAM. ANY STORMS THAT MOVE INTO THE AREA
WILL BE ABLE TO TAKE ADVANTAGE OF A FAVORABLE ENVIRONMENT WITH 30-45
KTS OF SHEAR, HIGH LAPSE RATES, AND SEASONABLE CAPE OF 3000-4000
J/KG TO BECOME STRONG TO SEVERE. THE PRIMARY THREAT WITH ANY STORMS
WOULD BE WIND, DUE TO TO SEASONABLY STRONG WINDS ALOFT. AS FOR WHERE
STORMS WOULD OCCUR, THE MOST LIKELY IS IN NORTHWEST ILLINOIS, AS THE
INSTABILITY GRADIENT WILL BE DRAPED ACROSS NORTHERN ILLINOIS.
HOWEVER, WHILE MUCH OF THE GUIDANCE KEEPS THIS OVER OUR NORTHWEST IL
COUNTIES, A FEW OF THE MODELS SHIFT IT FURTHER EASTWARD, LEADING TO
THE STORMS ALSO SHIFTING EASTWARD.
THE UNCERTAINTY IN WHERE STORMS COULD BE HAS LED TO SOME
UNCERTAINTY IN HEAT HEADLINES FOR MONDAY. HEAT AND HUMIDITY ARE
ONCE AGAIN LIKELY (60-80%), BUT THE DEGREE OF HOW HOT IT WILL BE
IS IN QUESTION. THERE ARE TWO POTENTIAL AVENUES FOR HOW THIS
COULD PLAY OUT. FIRST, IF THERE ARE LIMITED STORMS OVERNIGHT
THROUGH MONDAY MORNING, TEMPERATURES WILL BE SIMILAR TO TODAY'S
FORECAST HIGHS AND HEAT INDICES, IF NOT A DEGREE OR TWO WARMER.
THIS SCENARIO WOULD FAVOR AN EXTREME HEAT WARNING. HOWEVER, IF
STORM COVERAGE IS HIGHER AND CONVECTIVE DEBRIS LINGERS THROUGH
MONDAY MORNING, HIGHS COULD BE LIMITED TO THE UPPER 80S AND LOW
90S, WARRANTING A HEAT ADVISORY INSTEAD. THIS UNCERTAINTY IN
STORM COVERAGE AND EVOLUTION SUNDAY NIGHT HAS PROMPTED THE
CONTINUATION OF THE EXTREME HEAT WATCH AT THIS TIME.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
ISSUED AT 235 AM CDT SUN JUL 26 2026
MONDAY EVENING, A COLD FRONT SWEEPING THROUGH WILL PROVIDE SOME
REPRIEVE FROM THE HUMIDITY, THOUGH HOT TEMPERATURES ARE EXPECTED TO
CONTINUE THROUGH THE MIDDLE OF THE WEEK AS WE SIT ON THE EDGE OF A
RIDGE STRETCHED ACROSS THE INTERMOUNTAIN WEST. BY FRIDAY, THIS RIDGE
WILL RETROGRADE WESTWARD, ALLOWING FOR THE RING OF FIRE TO BE OVER
US ONCE MORE. THERE STILL REMAINS A SIGNAL FOR A SHORTWAVE TO MOVE
THROUGH THE FLOW FRIDAY, SUGGESTING THAT THIS MAY BE OUR NEXT CHANCE
FOR SOME RAINFALL AND COOLER TEMPERATURES.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1240 PM CDT SUN JUL 26 2026
A HAZY AFTERNOON WITH LINGERING MVFR CEILINGS ALONG AND EAST OF
THE MISSISSIPPI RIVER, WHICH WILL GRADUALLY LIFT AND SCOUR BY
MID-LATE AFTERNOON. ISOLATED STORMS COULD SPARK SOUTH OF I-80
THIS AFTERNOON, BUT TOO LOW OF CONFIDENCE TO INCLUDE IN MLI AND
BRL TAFS. FOR TONIGHT, A FEW UPPER LEVEL DISTURBANCES WILL
TRAVERSE THE REGION, AND IN SUCH A MOIST ATMOSPHERE IT WILL NOT
TAKE MUCH FOR SCATTERED STORMS TO DEVELOP. THE MAIN CHANCES LOOK
TO BE IN NORTHWEST ILLINOIS LATE TONIGHT AND MONDAY MORNING.
BECAUSE OF THIS CLOSE PROXIMITY, HAVE INCLUDED PROB30S FOR TSRA
AT DBQ AND MLI.
MORNING IFR, SUCH AS BEEN SEEN THE LAST TWO DAYS, IS CURRENTLY
NOT ANTICIPATED FOR MONDAY. HOWEVER, LINGERING HAZE IS LIKELY
AND SOME LOW CLOUDS WOULD BE POSSIBLE IN/NEAR NORTHWEST
ILLINOIS WHERE BOUNDARY LAYER RELATIVE HUMIDITY IS PREDICTED TO
BE THE HIGHEST.
OTHERWISE, SOUTHERLY WINDS WILL PREVAIL AT TAF SITES THROUGH
THE PERIOD, WITH SOME 10-12 KT SUSTAINED MONDAY AFTERNOON.
DVN WATCHES/WARNINGS/ADVISORIES
IA...EXTREME HEAT WARNING UNTIL 10 PM CDT MONDAY FOR IAZ040>042-
051>054-063>068-076>078-087>089-098-099.
IL...EXTREME HEAT WARNING UNTIL 10 PM CDT MONDAY FOR ILZ015-016-
024>026-034-035.
HEAT ADVISORY UNTIL 10 PM CDT MONDAY FOR ILZ001-002-007-009-
017-018.
MO...EXTREME HEAT WARNING UNTIL 10 PM CDT MONDAY FOR MOZ009-010.
SHORT TERM...ELLINGWORTH
LONG TERM...ELLINGWORTH
AVIATION...FRIEDLEIN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page