738
FXUS64 KOUN 181132
AFDOUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORMAN OK
632 AM CDT MON MAY 18 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 628 AM CDT MON MAY 18 2026
- THERE IS A RISK FOR STRONG TO SEVERE THUNDERSTORMS FROM THIS
AFTERNOON THROUGH TUESDAY.
- CRITICAL FIRE WEATHER CONDITIONS ARE POSSIBLE FOR FAR WESTERN
OKLAHOMA INTO WESTERN NORTH TEXAS THIS AFTERNOON
- VERY WARM TEMPERATURES ARE EXPECTED TODAY WITH COOLER WEATHER
BY TUESDAY.
NEAR TERM
(THROUGH MONDAY)
ISSUED AT 315 AM CDT MON MAY 18 2026
A NEGATIVELY-TILTED TROUGH WILL LIFT INTO THE CENTRAL PLAINS THIS
AFTERNOON WITH A TRAILING DRYLINE LOCATED ALONG THE 100TH
MERIDIAN. WITH THE SYNOPTIC-SCALE FORCING/ASCENT LIFTING TO THE
NORTHEAST, THUNDERSTORM DEVELOPMENT ALONG THE DRYLINE REMAINS
UNCERTAIN AS WARM MID-LEVEL TEMPERATURES AT THE BASE OF THE
ELEVATED MIXED LAYER (EML) WILL RESULT IN CAPPING INVERSION AT
~750 MB. IN ADDITION, LOW-LEVEL CONVERGENCE ALONG THE DRYLINE WILL
BE MINIMAL/WEAK WITH THE SURFACE LOW AND ATTENDANT BACKED WINDS
TO THE NORTHEAST OF OKLAHOMA. THE HIGHEST CHANCE FOR DEVELOPMENT
ALONG THE DRYLINE IS ACROSS NORTHWEST OKLAHOMA, WHICH IS IN
CLOSEST PROXIMITY TO THE WAVE. EVEN SO, THE CHANCE OF DEVELOPMENT
DURING THE LATE AFTERNOON/EARLY EVENING IS ONLY AROUND 20 TO 30%.
THE CHANCE OF DEVELOPMENT DECREASES WITH SOUTHWARD EXTENT ALONG
THE DRYLINE--BUT ISN'T ZERO.
IF THUNDERSTORMS DEVELOP, INSTABILITY AND VERTICAL WIND SHEAR
WILL BE SUFFICIENT FOR SUPERCELLS WITH CAPE BETWEEN 3000-3500 J/KG
AND 0-6 KM SHEAR BETWEEN 30 TO 35 KNOTS. BY EVENING, THE LOW-
LEVEL JET WILL AMPLIFY WITH 50 TO 60 KNOT WINDS. THE STRENGTHENING
LOW-LEVEL JET WILL INCREASE LOW-LEVEL WIND SHEAR, RESULTING IN
ENLARGED, CLOCKWISE- CURVED HODOGRAPHS THAT WILL BE FAVORABLE FOR
TORNADOES--INCLUDING STRONG TORNADOES. AS A RESULT, IF THERE ARE
ANY ONGOING SUPERCELLS IN THE EVENING, THEY WILL HAVE AN
INCREASING TORNADO POTENTIAL.
IN ADDITION TO THE DRYLINE, ANOTHER FEATURE WILL BE A SUBTLE WAVE
EMBEDDED IN THE SUBTROPICAL JET STREAM (STJ) THAT WILL LIFT
NORTHWARD INTO SOUTH CENTRAL/SOUTHEAST OKLAHOMA. THIS WAVE MAY
RESULT IN A FEW SHOWERS AND THUNDERSTORMS TODAY. WHILE IT APPEARS
LIKELY THIS ACTIVITY WILL BE ELEVATED AND ASSOCIATED WITH
ISENTROPIC/ASCENT WARM AIR ADVECTION, THERE IS A LOW CHANCE THIS
ACTIVITY COULD BECOME SURFACE-BASED WITH A RISK OF STRONG TO
SEVERE THUNDERSTORMS.
TO THE WEST OF THE DRYLINE, FIRE WEATHER CONDITIONS WILL BE A
CONCERN IN THE AFTERNOON. HOT TEMPERATURES, GUSTY SOUTHERLY WINDS,
AND LOW HUMIDITY WILL RESULT IN CRITICAL FIRE WEATHER CONDITIONS.
THE WORST FIRE WEATHER CONDITIONS WILL BE ACROSS THE OKLAHOMA AND
TEXAS PANHANDLES. HOWEVER, FAR WESTERN OKLAHOMA AND ADJACENT
PARTS OF WESTERN NORTH TEXAS WILL BE RIGHT ON THE EDGE. DEPENDING
ON THE EXACT LOCATION OF THE DRYLINE, THERE WILL LIKELY BE A VERY
TIGHT RELATIVE HUMIDITY GRADIENT NEAR THE 100TH MERIDIAN
(OKLAHOMA/TEXAS STATE LINE). THEREFORE, THE FIRE WEATHER WATCH WAS
UPGRADED TO A RED FLAG WARNING EXCEPT FOR JACKSON COUNTY. IT
COULD VERY WELL BE A SITUATION WHERE THE FIRE WEATHER CONDITIONS
ARE WORSE IN THE WESTERN PART OF THE COUNTIES COMPARED TO THE
EASTERN PART OF THE COUNTIES.
IN ADDITION TO THE RISK OF SEVERE AND FIRE WEATHER, A TIGHT
SURFACE PRESSURE GRADIENT WILL RESULT IN BREEZY SOUTHERLY WINDS
TODAY.
MAHALE
SHORT TERM
(MONDAY NIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 315 AM CDT MON MAY 18 2026
A COLD FRONT WILL ENTER NORTHERN OKLAHOMA LATE THIS EVENING,
WHICH WILL LIKELY RESULT IN A LINE OF THUNDERSTORMS DEVELOPING
ALONG THE FRONT. THE LINE OF THUNDERSTORMS WILL MOVE TO THE
SOUTHEAST MONDAY NIGHT INTO TUESDAY MORNING WITH THE COLD FRONT
WITH A THREAT FOR STRONG TO SEVERE THUNDERSTORMS. DAMAGING WIND
GUSTS AND EMBEDDED, QLCS TORNADOES WOULD BE THE POTENTIAL HAZARDS.
HOWEVER, THE TENDENCY FOR THE COLD FRONT TO UNDERCUT THE LINE OF
THUNDERSTORMS AND UNFAVORABLE SHEAR VECTORS/LINE ORIENTATION
SHOULD REDUCE THE QLCS TORNADO RISK. COOLER WEATHER AND NORTHERLY
WINDS ARE EXPECTED IN THE FRONT'S WAKE TUESDAY AFTERNOON.
ANOTHER WAVE IS FORECAST TO APPROACH LATE TUESDAY NIGHT INTO
WEDNESDAY, WHICH WILL RESULT IN INCREASING ISENTROPIC ASCENT/WARM
AIR ADVECTION TO THE NORTH OF THE COLD FRONT. WIDESPREAD ELEVATED
SHOWERS AND THUNDERSTORMS ARE POSSIBLE WITH THE POTENTIAL HAZARDS
BEING HEAVY RAINFALL/FLOODING AND HAIL. THE LOCATION WITH THE
HIGHEST CHANCE FOR HEAVY RAINFALL IS SOUTH CENTRAL/SOUTHEAST
OKLAHOMA.
MAHALE
LONG TERM
(THURSDAY THROUGH SUNDAY)
ISSUED AT 315 AM CDT MON MAY 18 2026
AN ACTIVE SUBTROPICAL JET STREAM (STJ) WITH SUBTLE WAVES LIFTING
INTO THE SOUTHERN PLAINS WILL RESULT IN A DAILY CHANCE OF
SHOWERS/STORMS THROUGH THE END THE WEEK INTO NEXT WEEKEND. AT THIS
TIME, THERE IS NO DAY THAT HAS AN APPRECIABLE RISK FOR SEVERE
WEATHER. TEMPERATURES ARE EXPECTED TO BE SEASONABLE FOR LATE MAY.
MAHALE
AVIATION
(12Z TAFS)
ISSUED AT 628 AM CDT MON MAY 18 2026
MVFR CONDITIONS ARE FORECAST TO GRADUALLY LIFT TOWARDS MID-DAY
WITH STRONG SOUTHERLY WINDS GUSTING UP TO 40 TO 50 MPH AT SOME
LOCATIONS. A COLD FRONT MOVES THROUGH LATE MONDAY NIGHT INTO
TUESDAY MORNING AND SHOWER/STORM CHANCES WILL INCREASE BY LATE
EVENING OVER NORTHERN OKLAHOMA AND PROGRESS SOUTHWARD OVERNIGHT.
CHANCES OF SEVERE STORMS ARE LOW DURING THE DAY AND INCREASE WITH
THE FRONTAL PASSAGE TONIGHT.
PRELIMINARY POINT TEMPS/POPS
OKLAHOMA CITY OK 86 61 71 55 / 10 80 40 80
HOBART OK 93 60 75 54 / 10 60 30 60
WICHITA FALLS TX 92 68 82 58 / 20 50 70 70
GAGE OK 96 49 73 46 / 10 20 0 10
PONCA CITY OK 89 58 70 53 / 10 80 30 30
DURANT OK 88 74 84 64 / 30 20 90 70
OUN WATCHES/WARNINGS/ADVISORIES
OK...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR OKZ004>027-
034>038.
RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 9 PM CDT THIS
EVENING FOR OKZ004-009-014-021-033-034.
TX...RED FLAG WARNING FROM 1 PM THIS AFTERNOON TO 9 PM CDT THIS
EVENING FOR TXZ083-084.
NEAR TERM...10
SHORT TERM...10
LONG TERM....10
AVIATION...01
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