448
FXUS61 KPBZ 190151
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
851 PM EST WED FEB 18 2026
WHAT HAS CHANGED
DENSE FOG ADVISORY ISSUED THROUGH 9AM THURSDAY FOR THE NORTHERN COUNTIES
OF WESTERN PA. UPDATE ON THE THUNDERSTORM POTENTIAL TOMORROW.
WINTER WEATHER HEADLINES REMAIN LOW OVER THE WEEKEND.
KEY MESSAGES
1) DENSE FOG ADVISORY ISSUED THROUGH 9AM THURSDAY.
2) ICE JAM POTENTIAL THROUGHOUT THE WEEK.
3) THUNDERSTORM CHANCES INCREASE THURSDAY NIGHT INTO FRIDAY
MORNING.
4) SNOW POTENTIAL OVER THE WEEKEND.
DISCUSSION
KEY MESSAGE 1...
DENSE FOG ADVISORY HAS BEEN ISSUED THROUGH 9AM FOR LAWRENCE,
BUTLER, ARMSTRONG, INDIANA, JEFFERSON, CLARION, FOREST, VENANGO,
AND MERCER COUNTIES. THERE HAVE BEEN SOME OBSERVATIONS WITH
VISIBILITY AROUND 0.25 MILES. WITH CLEARING SKIES AND WEAKENING
WIND, THE CHANCE FOR FOG IN THE AREA IS FORECAST TO INCREASE
OVERNIGHT WITH THE HIGHEST PROBABILITY BETWEEN 5AM-7AM.
KEY MESSAGE 2...
ABOVE-AVERAGE TEMPERATURES OVER THE PAST 48 HOURS AND CONTINUING
THROUGH FRIDAY WILL CAUSE RIVER ICE TO THAW AND BREAK UP ON MAIN
STREAM AND SMALLER TRIBUTARIES. AREAS WITH SIGNIFICANT BENDS
("HOT SPOTS") SHOULD BE MONITORED FOR ICE JAMS. WHILE RAINFALL
WILL BE MINIMAL IN THE NEXT 24 HOURS, INCREASED WATER FLOW
FRIDAY INTO SATURDAY COULD LEAD TO WATER BACKUP NEAR ANY ICE
JAMS.
KEY MESSAGE 3...
A NEW STORM SYSTEM IS EXPECTED TO DEVELOP OVER THE NORTHERN
GREAT PLAINS EARLY THURSDAY. IT WILL MOVE EAST AND MERGE WITH A
NEARLY STATIONARY LOW-PRESSURE DISTURBANCE OVER THE GREAT LAKES
LATE THURSDAY INTO EARLY FRIDAY.
THE CONVERGENCE OF WARM, MOIST AIR FROM THE SOUTHWEST AND
INCREASING VERTICAL WIND SHEAR TO PROMPT LIFT CREATES A WINDOW
OF THUNDERSTORM DEVELOPMENT BETWEEN 10PM THURSDAY TO 2AM FRIDAY.
DESPITE STRONG LOW-LEVEL SHEAR, OVERALL INSTABILITY IS LIMITED
("LACKLUSTER") DUE TO THE PRESENCE OF WARM AIR HIGHER IN THE
ATMOSPHERE, SUBSIDING THE GROWTH OF DEEP STORMS. THE BEST
POTENTIAL FOR STRONG TO SEVERE STORMS IS WEST OF FORECAST AREA,
NEAR INDIANA AND ILLINOIS, WHERE LOW-LEVEL MOISTURE IS AVAILABLE
TO OVERCOME THE WARM AIR ALOFT. HENCE THE STORM PREDICTION
CENTER (SPC) OVERLAYING A "SLIGHT" RISK FOR THAT NOTED REGION.
STORM CHANCES WILL LIKELY DECREASE BEFORE DAWN ON FRIDAY.
HOWEVER, LINGERING RAIN SHOWERS WILL LIKELY CONTINUE INTO LATE
FRIDAY MORNING BEFORE DRIER AND COOLER CONDITIONS RETURN.
KEY MESSAGE 4...
THE WEATHER PATTERN WILL SHIFT SIGNIFICANTLY THIS WEEKEND WITH A
RIDGE AXIS ADVANCING OVER THE WEST COAST AND A TROUGH ADVANCING
ACROSS THE GREAT LAKES. THIS SETUP WILL LEAD TO A RETURN OF
COOLER CONDITIONS AND THE POTENTIAL OF SNOW SUNDAY INTO MONDAY.
THE CHANCE OF MINOR IMPACTS IS LOW AREA-WIDE (20-30%), MEANING
WINTER HEADLINES ARE NOT EXPECTED. LOCALIZED UPSLOPING OVER THE
WEST VIRGINIA RIDGES MAY BE ENOUGH TO TRIGGER AN ADVISORY.
PROBABILITY OF 3 INCHES OF SNOW IN TUCKER COUNTY IN 24 HOURS IS
40% AT THE MOMENT.
AVIATION /01Z THURSDAY THROUGH MONDAY/
KEY MESSAGES...
- COMBINATION OF EITHER CLEARING SKIES OR TOP-DOWN MOISTENING
FAVORS WIDESPREAD IFR WITH AREAS OF FOG OVERNIGHT
- LOW PROBABILITY FOR THUNDERSTORMS EXIST TONIGHT (FKL/DUJ) AND
THURSDAY AFTERNOON (MOST TERMINALS)
------------------------------------------------------------
POST-FRONTAL CLEARING WILL WANE THIS EVENING AS DIURNAL COOLING
SUPPORTS INVERSION DEVELOPMENT WHICH WILL TEND TO LOCK TERMINALS
IN EITHER CLEAR CONDITIONS OR THE LOWER IFR STRATUS AT THE START
OF THE TAF PERIOD. FOR BOTH AREAS, THE EXPECTATION IS FOR IFR TO
LIFR CIG/VSBY TO DEVELOP BETWEEN 04Z-14Z PENDING STRENGTH OF
EITHER RADIATIONAL COOLING (ZZV/HLG/MGW) OR TOP-DOWN MOISTENING
(REST OF TERMINALS). TIMING AND DEGREE OF RESTRICTION FALLS IS
MORE UNCERTAINTY AND MAY BE HEAVILY INFLUENCED BY NEAR-BY
RESIDUAL SNOW PACKS AND/OR LOCAL TERRAIN.
THE OTHER ITEM THIS EVENING IS LOW PROBABILITY FOR THUNDERSTORMS
CROSSING FKL/DUJ ALONG A SAGGING FRONTAL BOUNDARY; TIMING FAVORS
02Z-05Z. THIS ALSO MAY DISRUPT FALLING CIG/VSBY TRENDS
TEMPORARILY.
GRADUAL MIXING AMID DIURNAL HEATING THURSDAY FAVORS A BRIEF
PERIOD OF VFR AT AREA TERMINALS (60-90% PROBABILITY) BEFORE A
LIFTING WARM FRONTAL BOUNDARY REINTRODUCES AREAS OF MVFR CIGS
AMID SCATTERED TO NUMEROUS RAIN SHOWERS (FAVORING WV HIGHER
TERRAIN). LIGHTNING CAN'T BE RULED OUT BUT PROBABILITY IS TOO
LOW AT THIS TIME FOR ANY TAF MENTION.
OUTLOOK...
SHOWERS AND LOW PROBABILITY THUNDERSTORMS ARE EXPECTED THURSDAY
EVENING INTO FRIDAY MORNING AHEAD OF A COLD FRONT. RESTRICTIONS
REMAIN LIKELY WITHIN THE PRE- AND POST-FRONTAL ENVIRONMENTS
BEFORE HIGH PRESSURE RETURNS VFR AREAWIDE FRIDAY AFTERNOON INTO
SATURDAY (THOUGH MVFR MAY LINGER NEAR FKL/DUJ).
PBZ WATCHES/WARNINGS/ADVISORIES
PA...DENSE FOG ADVISORY UNTIL 9 AM EST THURSDAY FOR PAZ007>009-
013>016-022-077-078.
OH...NONE.
WV...NONE.
DISCUSSION...HEFFERAN/LUPO
AVIATION...FRAZIER
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