686
FXUS63 KLOT 141917
AFDLOT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL
217 PM CDT THU MAY 14 2026
KEY MESSAGES
- CHANCE FOR PERIODIC SHOWERS ACROSS THE AREA TONIGHT. SCATTERED
STRONG STORM CHANCES AT TIMES LATE FRIDAY THROUGH THIS
WEEKEND.
- BETTER SHOT AT WIDESPREAD SHOWERS AND STORMS, SOME POSSIBLY
SEVERE, MONDAY INTO TUESDAY.
- TEMPERATURES TREND WARMER THROUGH THE WEEKEND AND INTO EARLY
NEXT WEEK.
DISCUSSION
ISSUED AT 215 PM CDT THU MAY 14 2026
SURFACE HIGH PRESSURE CENTERED OVER THE REGION WILL KEEP
CONDITIONS QUIET THROUGH THIS EVENING. A SUBTLE SHORT-WAVE AND
PUSH OF MID-LEVEL WAA TONIGHT WILL KICK OFF A ROUND OF SHOWERS
TONIGHT (AFTER 04Z). WITH A LACK OF INSTABILITY TONIGHT THE
RISK FOR ANY THUNDERSTORMS IS VERY LOW (LESS THAN 10%) AND
IMPACTS SHOULD BE MINIMAL. SHOWERS SHOULD DEPART TO THE EAST
MID-MORNING FRIDAY LEAVING THE REST OF THE DAY DRY WITH
TEMPERATURES PEAKING IN THE LOW TO MIDDLE 70S. WINDS ON FRIDAY
WILL INCREASE AS THEY BECOME SOUTHERLY, SUSTAINED WINDS OF 15-
20 MPH ARE EXPECTED THROUGH MUCH OF THE DAY WITH WIND GUSTS
PEAKING AROUND 25-30 MPH. REFS SHOWS A BRIEF PERIOD OF 20-40%
PROBABILITIES FOR GREATER THAN 30 MPH GUSTS DURING THE LATE
MORNING WITH DIMINISHING PROBS THROUGH THE AFTERNOON AS THE
PRESSURE GRADIENT SLACKS OFF.
CAMS ARE IN GENERAL AGREEMENT THAT ANOTHER SHORT-WAVE WILL EJECT OUT
OF THE SOUTHWEST LATE FRIDAY AND PASS THROUGH OTHERWISE ZONAL FLOW
ALOFT. THIS FEATURE WILL BRING THE NEXT CHANCE FOR THUNDERSTORMS TO
THE REGION LATE FRIDAY INTO EARLY SATURDAY MORNING. AHEAD OF THE
SHORT-WAVE SURFACE DEW POINTS ARE FORECAST TO INCREASE INTO THE MID
50S WHICH ALONG WITH AN EML CAUSING STEEPENING MID-LEVEL LAPSE RATES
(7-8 C/KM) WILL RESULT IN ELEVATED INSTABILITY VALUES OF 1000-1500
J/KG. 0-6KM SHEAR VALUES OF AROUND 50 KTS ARE ALSO EXPECTED DURING
THIS TIMEFRAME AS A 45-60KT JET STREAK PASSES OVER CENTRAL WI.
THIS WILL CREATE A PARAMETER SPACE CAPABLE OF SUPPORTING A FEW
MARGINALLY SEVERE ELEVATED THUNDERSTORMS ACROSS THE WESTERN HALF
OF THE FORECAST AREA WITH LARGE HAIL THE MAIN THREAT, HOWEVER,
SPORADIC DAMAGING WIND GUSTS ARE ALSO POSSIBLE.
A QUASI STATIONARY BOUNDARY IS EXPECTED TO SET UP SOMEWHERE ACROSS
THE REGION SATURDAY WHICH MAY PROVIDE THE FOCUS FOR ANOTHER ROUND OF
THUNDERSTORMS SATURDAY AFTERNOON/EVENING, HOWEVER, EXACTLY WHERE
THIS BOUNDARY SETS UP WILL IN PART BE TIED TO HOW THE EARLY
MORNING CONVECTION PLAYS OUT. SOUTH OF THIS BOUNDARY LOW-LEVEL
MOISTURE TRANSPORT WILL CONTINUE THROUGHOUT THE DAY SATURDAY
WITH DEW POINTS INCREASE INTO THE LOW TO MID 60S AND
TEMPERATURES WARMING INTO THE MID TO UPPER 70S RESULTING IN
1000-1500 J/KG OF SURFACE BASED INSTABILITY WHICH WOULD SUPPORT
AT LEAST ANOTHER ROUND OF STRONGER THUNDERSTORMS. HOWEVER, MID-
LEVEL CAPPING AND THE LACK OF A STRONGER FORCING MECHANISM MAY
LEAD TO MORE ISOLATED STORM COVERAGE.
A TROUGH DIGGING INTO THE INTERMOUNTAIN WEST LATER INTO THE WEEKEND
AND EARLY NEXT WEEK WILL RESULT IN PROLONGED PERIOD OF SOUTHWESTERLY
FLOW BRING MORE SUMMER LIKE CONDITIONS (HIGH TEMPERATURES IN MIDDLE
80S TO LOW 90S) TO THE REGION. ALONG WITH THE WARMTH THERE WILL
BE A CHANCE FOR THUNDERSTORMS EACH DAY THROUGH TUESDAY AS A
SERIES OF SHORT-WAVES MOVE ACROSS THE REGION. SUNDAY THE BEST
STORM CHANCES WILL COME DURING THE MORNING ON THE LEADING EDGE
OF AN AREA OF MIDDLE LEVEL WAA BEFORE THE AREA BECOMES CAPPED
DURING THE AFTERNOON. MONDAY THE REGION IS FORECAST TO BE WELL
INTO THE WARM SECTOR WITH DEW POINTS IN THE UPPER 60S AND TEMPS
IN THE 80S LEADING TO IMPRESSIVE SURFACE INSTABILITY, HOWEVER,
THE LACK OF A CLEAR FORCING MECHANISM LEADS TO LOW CONFIDENCE IN
CONVECTIVE EVOLUTION MONDAY. AT THIS POINT THE TIMEFRAME WITH
THE MOST AREAL COVERAGE OF STORMS IS LATE TUESDAY AS A WELL
DEFINED COLD FRONT IS FORECAST TO SWINGS ACROSS THE FORECAST
AREA.
KAISER
AVIATION /18Z TAFS THROUGH 00Z SATURDAY/
ISSUED AT 1230 PM CDT THU MAY 14 2026
SURFACE HIGH PRESSURE WILL PASS TO THE EAST THROUGH THE
AFTERNOON WITH WINDS TRENDING SOUTHERLY AT KRFD WHILE AN
EASTERLY ONSHORE COMPONENT DEVELOPS AT KORD/KMDW. HOWEVER,
WINDS WILL REMAIN MAINLY AT OR BELOW 10 KTS THIS AFTERNOON.
WINDS WILL BECOME SOUTHEASTERLY OVERNIGHT WITH SOUTH TO
SOUTHWESTERLY WINDS INCREASING ON FRIDAY, GUSTING 20 TO 25 KTS
AT TIMES BY MID-MORNING.
THERE'S A SMALL CHANCE (20-30%) FOR A SHOWER EARLY FRIDAY, BUT
HIGHER CHANCES WILL BE SOUTH OF THE AREA TERMINALS. MAINLY VFR
CONDITIONS WILL CONTINUE THROUGH FRIDAY, ALTHOUGH THERE IS A LOW
PROBABILITY (20-40%) FOR A BRIEF PERIOD OF MVFR CEILINGS FRIDAY
MORNING.
NWS CHICAGO
LOT WATCHES/WARNINGS/ADVISORIES
IL...NONE.
IN...NONE.
LM...NONE.
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