186
FXUS62 KRAH 180451
AFDRAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1250 AM EDT MON MAY 18 2026
WHAT HAS CHANGED
* MINOR TWEAKS TO HIGHS AND HEAT INDEX VALUES THROUGH
WEDNESDAY, ALTHOUGH THE MESSAGE REMAINS THE SAME.
KEY MESSAGES
AS OF 1240 PM SUNDAY...
1) HOT AND MAINLY DRY THROUGH WEDNESDAY.
2) INCREASINGLY UNSETTLED STARTING WED NIGHT, WITH MORE
SEASONABLE TEMPERATURES.
DISCUSSION
AS OF 1240 PM SUNDAY...
KEY MESSAGE 1...
HOT AND MAINLY DRY THROUGH WEDNESDAY.
AN UNSEASONABLY STRONG MID/LOW-LEVEL ANTICYCLONE AND STEEP MID-
LEVEL LAPSE RATES (ASSOCIATED WITH A MODIFIED EML) SAMPLED IN
THE 12Z RAOB DATA OVER CAROLINAS AND PORTION OF THE SOUTHEAST,
WILL KEEP CONDITIONS CAPPED AND VOID OF PRECIPITATION AMIDST
UNSEASONABLY MOIST DEEP-LAYER MOISTURE IN PLACE. WARM
TEMPERATURES THOUGH THE MID/LOW-LVLS WILL EXCEED THE 90TH
PERCENTILE THROUGH AT LEAST WEDNESDAY AND SUPPORT SEVERAL DAYS
OF HOT CONDITIONS AT THE SURFACE WHEN TEMPERATURES SHOULD
REGULARLY ECLIPSE 90 DEGREES BY MID- AFTERNOON.
GIVEN CENTRAL NC'S POSITION WITHIN THE DESCRIBED WEATHER
PATTERN ABOVE, THERE ARE MINIMAL FAILURE MODES AND REASONABLY
HIGH CONFIDENCE IN THE FORECAST HIGH TEMPERATURES THROUGH WED.
HOWEVER, FORECAST CONFIDENCE ON MIXING OUT OF DEW POINTS IN THE
AFTERNOON IS SLIGHTLY LOWER AND WILL RESULT IN FLUCTUATIONS IN
THE DAILY MAXIMUM HEAT INDEX VALUES. LEANING ON EXPERIMENTAL
HEATRISK, WIDESPREAD AND PROLONGED MODERATE RISK (LEVEL 2 OUT OF
4) IS EXPECTED THROUGH WED. THIS LEVEL AND DURATION OF
UNSEASONABLY WARM TEMPERATURES WILL PRIMARILY AFFECT ANYONE
SENSITIVE TO THE HEAT, BUT ANY OUTDOOR ACTIVITIES IN THE SUN
DURING PEAK HEATING SHOULD BE MONITORED CLOSELY FOR SIGNS OF
HEAT EXHAUSTION. TAKE BREAKS IN THE SHADE/INDOORS OFTEN AND MAKE
SURE ADEQUATE HYDRATION IS AVAILABLE.
REMINDER, THE TEMPERATURE FORECAST IS THE EXPECTED TEMPERATURE
IN THE SHADE AND DOES NOT ACCOUNT FOR ADDITIVE AFFECTS FROM
DIRECT SUNLIGHT. WET-BULB GLOBE TEMPERATURE (WBGT) DOES TAKE
THIS INTO ACCOUNT, BUT IS SENSITIVE TO INCOMING SOLAR RADIATION,
AND WIND SPEED. IF YOU WOULD LIKE TO KNOW MORE, PLEASE SEE
WEATHER.GOV/RAH/WBGT FOR MORE INFORMATION.
KEY MESSAGE 2...
INCREASINGLY UNSETTLED STARTING WED NIGHT, WITH MORE SEASONABLE
TEMPERATURES.
THE UNSEASONABLY STRONG RIDGE WILL GRADUALLY WEAKEN AND LOSE
ITS GRIP ON THE CAROLINAS AND PORTIONS OF THE SOUTHEAST AS THE
MID/LOW-LVL ANTICYCLONE SETTLES BACK OVER BERMUDA BY MID-WEEK.
THE MID/UPPER LEVEL TROUGH AXIS WELL BECOME ELONGATED ACROSS THE
CONUS AS THE NORTHERN WAVE PROGRESSIVELY RIDES THE
INTERNATIONAL BORDER TO THE NORTH AND A SOUTHERN PORTION
GRADUALLY PINCHES OFF OVER SOUTHERN PLAINS INTO THE WEEKEND.
OUR FIRST CHANCE FOR RAIN MAY COME AS EARLY AS WED EVENING IN
THE NORTHWEST PIEDMONT, BUT MORE LIKELY THURS INTO FRI AS A WEAK
TO MODERATELY UNSTABLE AIRMASS WILL PRECEDE A BACKDOOR COLD
FRONT AS IT SHIFTS ACROSS THE AREA THURS AFTERNOON/EVENING.
SHOWERS AND SOME ISOLATED STORMS WILL BE POSSIBLE ALONG THE
FRONT, GIVEN FAVORABLE DIURNAL PASSAGE AS OF THE LATEST
FORECAST, WITH WEAK 925MB FGEN AND LOW/MID-LVL WAA ATOP THE
FRONT SHOULD SUPPORT A PERIOD OF LIGHT STRATIFORM RAIN IN ITS
WAKE INTO FRI, POTENTIALLY SETTING UP A BRIEF CLASSICAL-CAD INTO
FRI.
THE SURFACE HIGH WILL BE VERY TRANSITORY ACROSS THE NORTHERN
MID-ATLANTIC AND SHOULD NOT SUSTAIN CLASSICAL CAD INTO THE
WEEKEND. FRI AFTERNOON/NIGHT SHOULD SEE A TRANSITION BACK TO A
SOUTHERLY FLOW REGIME. THIS SHOULD SET THE STAGE FOR A MORE
TYPICAL EARLY SUMMERTIME PATTERN FOR DIURNAL SHOWERS/STORMS
DURING THE AFTERNOON/EVENING FOCUSED AROUND THE SEA-BREEZE AND
TERRAIN CIRCULATIONS.
AVIATION /05Z MONDAY THROUGH FRIDAY/
AS OF 1250 AM MONDAY...
TAF PERIOD: WITH HIGH PRESSURE OFFSHORE, THE FORECAST SHOULD BE
QUIET WITH VFR ALMOST A CERTAINTY. THE ONE EXCEPTION WILL BE AROUND
SUNRISE AT FAY, WHERE YESTERDAY THERE WAS AN MVFR CEILING FOR ABOUT
90 MINUTES, AND VERTICAL SOUNDINGS SHOW THIS SHOULD BE A POSSIBILITY
AGAIN THIS MORNING. OTHERWISE, CONDITIONS SHOULD BE MOSTLY CLEAR
WITH SOUTHWEST WIND.
OUTLOOK: MVFR CEILINGS WILL BE POSSIBLE BRIEFLY AT FAY AND RWI
TUESDAY AND WEDNESDAY MORNINGS, OTHERWISE DRY VFR CONDITIONS ARE
FORECAST THROUGH WEDNESDAY. THE CHANCE OF RAIN WILL INCREASE FROM
NORTHWEST TO SOUTHEAST WEDNESDAY NIGHT, WITH RESTRICTIONS AND
SHOWERS EXPECTED THURSDAY AND FRIDAY.
CLIMATE
RECORD HIGH TEMPERATURES:
MAY 18: KGSO: 95/1911 KRDU: 95/1906 KFAY: 96/1911
MAY 19: KGSO: 96/1911 KRDU: 95/1962 KFAY: 96/2022
MAY 20: KGSO: 95/1917 KRDU: 96/2022 KFAY: 99/2022
RECORD HIGH MINIMUM TEMPERATURES:
MAY 18: KGSO: 70/2015 KRDU: 72/1896 KFAY: 71/2018
MAY 19: KGSO: 68/2018 KRDU: 70/2022
MAY 20: KGSO: 68/2022 KRDU: 69/2019 KFAY: 71/2022
MAY 21: KGSO: 67/2022 KRDU: 71/1898 KFAY: 71/2025
RAH WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...AS
AVIATION...GREEN
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