932
FXUS64 KMRX 301746
AFDMRX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MORRISTOWN TN
1246 PM EST THU JAN 30 2025
..NEW AVIATION
UPDATE
ISSUED AT 1115 AM EST THU JAN 30 2025
CLOUDS ARE INCREASING AHEAD OF NEXT SYSTEM. A FEW ISENTROPICALLY
DRIVEN SHOWERS WERE FORMING IN A ENHANCED AREA OF LIFT OVER THE
NORTHERN PLATEAU AND EXTENDING EAST INTO THE CENTRAL VALLEY. THIS
AREA SLOWLY LIFTS NORTHEAST THROUGH THE AFTERNOON. TEMPERATURES
AT LATE MORNING ARE IN THE 40S REGIONWIDE, WITH A 50 AT
CHATTANOOGA. EXPECT CLOUDS TO CONTINUE TO INCREASE WITH MORE
STEADY RAIN STAYING TO THE WEST UNTIL LATE TODAY OR THIS EVENING.
SHORT TERM MODELS BRING THE PRECIPITATION NORTHEASTWARD MAINLY
WEST AND NORTH OF THE FORECAST AREA UNTIL LATER TONIGHT. HAVE
MADE SOME CHANGES TO KEEP POPS LOWER EAST AND SOUTH AND HIGHER IN
THE WEST. MOST LOCATIONS MAY ONLY SEE A TRACE OR A FEW HUNDREDTHS
BEFORE SUNSET TONIGHT. UPDATED FORECAST SENT.
SHORT TERM
(TODAY THROUGH FRIDAY)
ISSUED AT 342 AM EST THU JAN 30 2025
KEY MESSAGES:
1. MEDIUM CHANCES FOR A NARROW BAND OF LIGHT RAIN TO TRAVERSE THE
AREA TODAY.
2. GUSTY MOUNTAIN AND FOOTHILL WINDS OVERNIGHT TONIGHT, WIND
ADVISORY IN EFFECT.
3. STEADIER RAIN TO DEVELOP OVERNIGHT AND TO LAST THROUGH TOMORROW.
DISCUSSION:
GUIDANCE HAS BEEN PERSISTENT WITH SHOWING A NARROW BAND OF LIGHT
RAIN TRAVERSING FROM CHATTANOOGA UP VALLEY TO THE TRI-CITIES AND
VIRGINIA FROM THIS MORNING TO LATE THIS AFTERNOON. HOWEVER, NOT
CERTAIN HOW MUCH RAIN WILL BE ABLE TO REACH THE SURFACE AS IT IS
DEPENDENT ON HOW MUCH OF THE ISENTROPICALLY DRIVEN SHOWERS WILL BE
EATEN AWAY BY THE LOW LEVEL DRY AIR MONSTER. SOUNDINGS HAVE A
FAIRLY SIGNIFICANT DRY AIRMASS IN THE LOWEST 2 KM OF ATMOSPHERE,
OWING TO OUR DRY WEATHER LEADING INTO THIS EVENT. AS SUCH, I TOOK
THE LIBERTY OF SLIGHTLY DECREASING BOTH POPS AND QPF FOR TODAY TO
COMPENSATE. ALWAYS HARD TO FIGURE HOW TO MESSAGE RAIN CHANCES
WHEN THE OVERALL QPF FOR THE DAYLIGHT HOURS IS ONLY A FEW
HUNDREDTHS OF AN INCH IN THE VALLEY, WITH SOME BUST POTENTIAL OF
NO RAIN REACHING. THE LAST FEW HRRR RUNS HAVE BEEN SHOWING MORE
POPCORN SHOWERS DEVELOPING OVERNIGHT, BUT THE MAIN BATCH OF RAIN IS
FRIDAY MORNING THROUGH FRIDAY AFTERNOON. THE STEADY RAIN SHOULD
TAPER FROM WEST TO EAST AS THE AFTERNOON HOURS PROGRESS TOMORROW.
EVENT TOTAL RAINFALL SHOULD RANGE BETWEEN 0.5 AND 1.0 INCH OF
RAIN, WITH THE NORTHERN PLATEAU ALONG WITH LEE & WISE COUNTIES IN
VIRGINIA STANDING THE BEST CHANCES TO GET AN INCH OF RAINFALL.
I WENT AHEAD AND ISSUED A WIND ADVISORY FOR THE EAST TENNESSEE
MOUNTAINS FOR TONIGHT INTO TOMORROW MORNING. FLOW ALOFT WILL
INCREASE TONIGHT TO 45 KNOTS ON THE NC SIDE, 55 KNOTS OVER THE
TENNESSEE VALLEY SIDE OF THE MOUNTAINS. HREF BRINGS WIND GUSTS UP
TO 50 TO 55 MPH IN THE SMOKY MOUNTAINS, LESSER VALUES NORTH AND
SOUTH OF THE NATIONAL PARK. WINDS ALOFT WILL BE PIVOTING FROM A
SOUTH-SOUTHWESTERLY VECTOR TO MORE OF A SOUTHWESTERLY AKA
PARALLEL TO TERRAIN FLOW AS FRIDAY MORNING BEGINS. HREF ALSO HAS A
50% CHANCE OF A WIND GUST EXCEEDING 60 MPH IN THE SMOKIES, WHICH
SEEMS FAIR GIVEN THE BALANCE BETWEEN THE STRENGTH OF THE FLOW AND
THE ORIENTATION OF SAID FLOW. SHOULD BE A PRETTY TYPICAL WIND
EVENT FOR THOSE NEAR THE MOUNTAINS. WINDS WILL STEADILY DECREASE
THROUGH THE DAY ON FRIDAY.
LONG TERM
(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 342 AM EST THU JAN 30 2025
KEY MESSAGES:
1. ABOVE NORMAL TEMPERATURES FOR THE EXTENDED PERIOD.
2. DRIER FOR THE WEEKEND.
3. RAIN CHANCES RETURN BY MIDWEEK.
DISCUSSION:
THE AXIS OF THE UPPER LEVEL SHORT WAVE TROUGH JUST TO OUR WEST WILL
SWING ACROSS OUR AREA FRIDAY NIGHT, AND ALTHOUGH THE BETTER MOISTURE
WILL ALREADY BE OFF TO OUR EAST WITH THE EXITING COLD FRONT, THERE
STILL MAY BE A FEW RAIN SHOWERS AROUND ESPECIALLY NORTH. SURFACE
HIGH PRESSURE WILL BE BUILDING IN FOR SATURDAY WITH WESTERLY UPPER
LEVEL FLOW AS THE PATTERN BECOME MORE ZONAL, AND WE WILL REMAIN
UNDER QUASI-ZONAL FLOW ALOFT FOR THE REMAINDER OF THE PERIOD. A WEAK
AND MOISTURE STARVED COLD FRONT MAY SAG INTO OUR AREA SOMETIME IN
THE MONDAY/MONDAY NIGHT PERIOD, BUT RIGHT NOW THIS LOOKS LIKELY TO
BE PRECIP FREE. WE WILL SEE MAINLY DRY CONDITIONS FOR THE WEEKEND
INTO TUESDAY, ALONG WITH ABOVE NORMAL TEMPERATURES. MODELS ARE IN
POOR AGREEMENT BY THE END OF THE PERIOD SO CONFIDENCE LEVEL IS NOT
HIGH, BUT THE NEXT SYSTEM APPROACHING FROM THE WEST MAY BE CLOSE
ENOUGH TO BRING SHOWERS TO THE AREA BY WEDNESDAY.
AVIATION
(18Z TAFS)
ISSUED AT 1240 PM EST THU JAN 30 2025
VFR CONDITIONS TO CONTINUE UNTIL LATE TONIGHT AND EARLY FRIDAY
WHEN MVFR CONDITIONS ENTERS SOUTHEAST TN. A FEW SPOTS OF LIGHT
RAIN THIS AFTERNOON AT TYS AND TRI, BUT NO VIS RESTRICTIONS
LIKELY. TONIGHT SHOWER COVERAGE WILL GRADUALLY INCREASE FROM
SOUTHWEST TO NORTHEAST AND BECOME A STEADY RAIN AREAWIDE BY ABOUT
12Z WITH CIGS GRADUALLY DECREASING. A PERIOD OF LLWS STARTING BETWEEN
03-06Z AND ENDING ABOUT 12-15Z LOOKS LIKELY, GIVEN THE STRENGTHENING
SOUTHERLY FLOW ALOFT. NOT SURE IF WIND GUSTS WILL BE ABLE TO REACH
TO THE SURFACE UNTIL AROUND 12Z AT CHA AND TYS AND THEN 15Z FOR
TRI.
PRELIMINARY POINT TEMPS/POPS
CHATTANOOGA AIRPORT, TN 52 63 43 60 / 70 90 10 0
KNOXVILLE MCGHEE TYSON AIRPORT, TN 48 60 42 57 / 60 100 20 0
OAK RIDGE, TN 46 59 41 57 / 80 90 20 0
TRI CITIES AIRPORT, TN 45 58 41 54 / 80 100 20 10
MRX WATCHES/WARNINGS/ADVISORIES
NC...NONE.
TN...WIND ADVISORY FROM 7 PM THIS EVENING TO 10 AM EST FRIDAY FOR
BLOUNT SMOKY MOUNTAINS-COCKE SMOKY MOUNTAINS-SEVIER SMOKY
MOUNTAINS-SOUTHEAST CARTER-SOUTHEAST GREENE-SOUTHEAST
MONROE-UNICOI.
VA...NONE.
SHORT TERM...TD
AVIATION...TD
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