635
FXUS64 KLZK 202354
AFDLZK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LITTLE ROCK AR
554 PM CST FRI DEC 20 2024
..NEW SHORT TERM, LONG TERM, AVIATION
SHORT TERM
(THIS EVENING THROUGH SUNDAY)
ISSUED AT 1208 PM CST FRI DEC 20 2024
EARLY AFTERNOON WATER VAPOR SATELLITE IMAGERY SHOWED A STRONG
UPPER LEVEL LOW PRESSURE SYSTEM OVER THE EASTERN CONTINENTAL
UNITED STATES (CONUS) WITH A BROAD UPPER LEVEL RIDGE OVER THE
CONUS ROCKY MOUNTAINS. JUST EAST OF THE APEX OF THE RIDGE WAS A
COMPACT, BUT RELATIVELY STRONG SHORTWAVE TROUGH LOCATED OVER
EASTERN MONTANA. THIS FLOW REGIME LEFT ARKANSAS UNDER NORTHWEST
FLOW ALOFT IN THE TRANSITION ZONE BETWEEN THESE TWO DOMINANT UPPER
LEVEL FEATURES. AT THE SURFACE, REGIONAL OBSERVATIONS SHOWED A
COLD FRONT OVER FAR SOUTHERN ARKANSAS, CONTINUING TO MOVE SOUTH
INTO LOUISIANA AND ACROSS MIDDLE MISSISSIPPI THIS AFTERNOON.
BREEZY NORTHWESTERLY WINDS CONTINUED TO USHER IN COLD AND DRY AIR
ACROSS THE STATE, BUT DESPITE THE FAIRLY ROBUST COLD AIR ADVECTION
REGIME IN PLACE, DAYTIME HEATING WAS SLIGHTLY OUTPACING THE
TRANSPORT OF COLD AIR ALLOWING TEMPERATURES TO CLIMB APPROXIMATELY
10 DEGREES ABOVE PRE-FRONTAL TEMPERATURES THIS MORNING. VISIBLE
SATELLITE IMAGERY SHOWED CLEAR SKIES IN PLACE ACROSS THE STATE AND
THE 12Z NWS LITTLE ROCK WEATHER BALLOON SAMPLED A VERY DRY LOW
LEVEL AIRMASS WITH HUMIDITY VALUES LESS THAN 30 PERCENT THROUGH
THE 925 TO 500 MB LAYER ALOFT.
DESPITE IT'S SOMEWHAT STRONG APPEARANCE ON VISIBLE SATELLITE
IMAGERY, THE EASTERN MONTANA SHORTWAVE TROUGH IS EXPECTED TO PASS
OVER NORTHEAST ARKANSAS EARLY SATURDAY MORNING WITH LITTLE
NOTICEABLE CHANGE TO SURFACE SENSIBLE WEATHER FOLLOWING SO
CLOSELY BEHIND THE PASSAGE OF THE LARGE UPPER TROUGH THAT DROVE
THROUGH THE LARGE AIRMASS EXCHANGE WITH THE PASSAGE OF TODAY'S
COLD FRONT. IT MAY TEMPORARILY BRING SOME HIGH CLOUDS OVER THE
NORTHEAST AND EASTERN PORTION OF THE STATE SATURDAY MORNING,
HOWEVER IN ITS WAKE, IT WILL SIMPLY REINFORCE LARGE SCALE FORCING
FOR SUBSIDENCE FOR APPROXIMATELY 24 HOURS OVER THE NATURAL STATE.
BECAUSE SKIES WERE ALREADY EXPECTED TO BE CLEAR, THERE'S NO WAY TO
CHARACTERIZE THE SKIES AS BEING "SUPER CLEAR", SO DESPITE THE
COOLER AND DRIER CONDITIONS ACROSS THE STATE, THE ADDITIONAL
SUBSIDENCE WILL SIMPLY ALLOW YOU TO SOAK UP SOME POSSIBLY MUCH
NEEDED VITAMIN-D IF YOU HEAD OUTDOORS SATURDAY.
AFTER SUNSET TONIGHT, BREEZY NORTHWESTERLY WINDS WILL SUBSIDE AS
SURFACE HIGH PRESSURE BUILDS INTO PLACE. THE RAPID ONSET OF THE
NOCTURNAL INVERSION UNDER OPTIMAL RADIATIONAL COOLING CONDITIONS
WILL CAUSE THE WINDS TO BECOME LIGHT AND VARIABLE QUICKLY AFTER
SUNSET, AND TEMPERATURES ARE EXPECTED TO FALL WELL BELOW FREEZING
ACROSS THE ENTIRE STATE. WITH PLENTIFUL SUNSHINE ON SATURDAY,
DESPITE BEING THE SHORTEST DAY OF THE YEAR, WE ARE EXPECTED TO GET
ENOUGH DAYLIGHT IN TO BRING TEMPERATURES UP A GOOD 20 TO 25
DEGREES FROM MORNING LOWS, WITH HIGHS TOPPING OUT IN THE 40S FOR
MOST LOCATIONS SATURDAY AFTERNOON. SURFACE HIGH PRESSURE AND ITS
ASSOCIATED CONTINENTAL POLAR AIRMASS WILL BEGIN TO SLIDE OFF TO
THE EAST ON SUNDAY AS THE UPPER LEVEL RIDGE OVER THE ROCKIES
BREAKS DOWN AND SLIDES EAST OVER THE CENTRAL CONUS. THIS WILL
CAUSE WARM AIR ADVECTION TO BEGIN ALOFT FAIRLY QUICKLY DURING THE
DAY ON SUNDAY ACROSS ARKANSAS, ALTHOUGH SURFACE WINDS WILL REMAIN
EASTERLY, DELAYING OUR ABILITY TO FEEL THE WARM AIR ADVECTION HERE
ON THE GROUND FOR AT LEAST 24 HOURS. AS SUGGESTED ABOVE, ON SUNDAY
THE WARM AIR ADVECTION WILL ESSENTIALLY BUILD AN INVERSION ALOFT
OVER THE STATE AND WITHIN THIS INVERSION LAYER, PERSISTENT WARM
AIR ADVECTION ALOFT WILL TAP INTO SOME MEAGER LOW-LEVEL MOISTURE
OVER THE SOUTHERN PLAINS CAUSING A FEW CLOUDS TO DEVELOP ON THE
ELEVATED WARM AIR ADVECTION/ISENTROPIC LIFT REGIME OVER THE STATE
SUNDAY AFTERNOON. AS A RESULT, SUNDAY MORNING LOWS ARE EXPECTED
LONG TERM
(SUNDAY NIGHT THROUGH NEXT FRIDAY)
ISSUED AT 543 PM CST FRI DEC 20 2024
TO
START OFF THE DAY WELL BELOW FREEZING ONCE AGAIN WITH MOST
LOCATIONS FALLING INTO THE 20S AGAIN, BUT SUNDAY AFTERNOON HIGHS
ARE EXPECTED TO BE A FEW DEGREES WARMER THAN SATURDAY WITH WARM
AIR ADVECTION AIDING DAYTIME HEATING BEFORE CLOUDS SET IN SUNDAY
AFTERNOON.
CAVANAUGH
LONG TERM
(SUNDAY NIGHT THROUGH NEXT FRIDAY)
ISSUED AT 1208 PM CST FRI DEC 20 2024
PICKING UP WHERE THE SHORT TERM FORECAST LEFT OFF, THE PERSISTENT
WARM AIR ADVECTION AND HUMID ISENTROPIC LIFT REGIME IN THE
INVERSION ALOFT WILL LEAD TO EXPANDED CLOUD COVER OVER ALL OF
ARKANSAS FOR SUNDAY NIGHT INTO MONDAY MORNING. THE EXPANSION OF
THIS CLOUD LAYER SEVERAL THOUSAND FEET ALOFT WILL HELP BLANKET THE
STATE SUNDAY NIGHT, RE-RADIATING HEAT BACK TO THE SURFACE
THROUGHOUT THE OVERNIGHT HOURS, KEEPING OVERNIGHT TEMPERATURES AT
LEAST 5 TO 10 DEGREES WARMER THAN THEY WILL BE THIS WEEKEND. AS A
RESULT, MOST AREAS WILL REMAIN JUST ABOVE FREEZING TO START THE
DAY ON MONDAY MORNING WITH THE EXCEPTION OF FAR NORTHEAST ARKANSAS
WHERE THE CLOUD COVER IS EXPECTED TO EXPAND TO LAST.
PERSISTENT WARM AND HUMID AIR ADVECTION ALOFT WILL LEAD TO MOSTLY
CLOUDY SKIES ON MONDAY ACROSS ARKANSAS, HOWEVER THE WARM AND HUMID
AIR ADVECTION IS EXPECTED TO EXPAND FROM ELEVATED ONLY TO SURFACE
BASED, ALLOWING TEMPERATURES TO INCREASE BY A GOOD 20 TO 25
DEGREES ON MONDAY DESPITE THE LACK OF DIRECT SUNSHINE FOR MOST
LOCATIONS. MONDAY AFTERNOON HIGHS ARE EXPECTED TO TOP OUT IN THE
50S ACROSS MOST OF THE STATE WITH SOME 60 DEGREE HIGHS POSSIBLE
ACROSS FAR SOUTHERN ARKANSAS. THE EXPANSION OF WARM HUMID
ADVECTION FROM ALOFT TO THE SURFACE WILL ALSO SHUNT THE DRY,
CONTINENTAL POLAR AIRMASS OFF TO THE EAST ALLOWING FOR INCREASED
RAIN CHANCES ACROSS ARKANSAS AS EARLY AS MONDAY AFTERNOON. RAIN
SHOWERS ON MONDAY ARE EXPECTED TO BE RELEGATED PRIMARILY TO
NORTHWEST ARKANSAS DURING THE DAY AND WILL REMAIN SPOTTY IN
COVERAGE UNTIL UPPER LEVEL SUPPORT IN THE FORM OF LARGE SCALE
FORCING FOR ASCENT BEGINS TO SPREAD OVER THE REGION FROM WEST TO
EAST MONDAY NIGHT INTO TUESDAY (CHRISTMAS EVE) MORNING.
DURING THE DAY ON CHRISTMAS EVE, LARGE SCALE WARM AIR ADVECTION
WILL COUPLE WITH LARGE SCALE FORCING FOR ASCENT IN THE FORM OF
DIFFERENTIAL POSITIVE VORTICITY ADVECTION (PVA) WITH A LARGE
UPPER LEVEL LOW PRESSURE SYSTEM CROSSING THE GREAT PLAINS FROM THE
WEST. THIS SOMEWHAT SLOW MOVING UPPER TROUGH WILL BRING NEARLY
CERTAIN RAIN CHANCES OVER ALL OF ARKANSAS THROUGHOUT THE DAY ON
CHRISTMAS EVE MAKING FOR A WET DAY FOR MOST FOLKS ON THIS
TYPICALLY HEAVY DAY OF TRAVEL. AT THIS TIME THE RECOVERY OF WARM
HUMID AIR AT THE LOW-LEVELS IS EXPECTED TO BE TOO LIMITED TO
SUPPORT ANY CHANCE OF SEVERE WEATHER, AND IN FACT, IT MAY NOT BE
ENOUGH TO GET THUNDERSTORMS IN GENERAL. EXPECT MOST OF THE RAIN TO
FALL ON CHRISTMAS EVE AS LIGHT TO MODERATE RAIN SHOWERS, WITH
EMBEDDED ISOLATED THUNDERSTORMS POSSIBLE. SEVERE STORMS DO NOT
APPEAR TO BE SUPPORTED ACROSS ARKANSAS AT THIS TIME, HOWEVER WE
WILL CLOSELY WATCH LOW-LEVEL MOISTURE RECOVERY AND SEE IF MOISTURE
RECOVERY IS STRONGER THAN FORECAST ONCE THIS PROCESS BEGINS ON
MONDAY.
RAIN CHANCES ON CHRISTMAS DAY WILL DEPEND ON THE SPEED OF THE
UPPER TROUGH THAT LOOKS TO ALMOST CERTAINLY BRING WIDESPREAD RAIN
SHOWERS ACROSS ARKANSAS ON CHRISTMAS EVE. THE SLOWER THE UPPER
TROUGH MOVES EAST, THE LONGER RAIN CHANCES WILL LINGER ACROSS THE
STATE ON CHRISTMAS DAY. RIGHT NOW MODELS SEEM TO SUGGEST THAT RAIN
WILL LINGER ACROSS MUCH OF CENTRAL AND EASTERN ARKANSAS AT LEAST
THROUGH THE MORNING HOURS OF CHRISTMAS DAY, WITH RAIN POTENTIALLY
COMING TO AN END FROM WEST TO EAST ACROSS THE STATE DURING THE
AFTERNOON HOURS OF THE DAY. IF THE TROUGH IS A BIT FASTER TO CLEAR
THE STATE, RAIN CHANCES COULD DIMINISH FASTER THAN THIS. EITHER
WAY, RAINFALL IS NOT EXPECTED TO BE AS HEAVY ON CHRISTMAS DAY, AND
THE THREAT FOR THUNDERSTORMS SHOULD REMAIN EAST OR SOUTH OF THE
STATE. TEMPERATURES ON CHRISTMAS EVE AND DAY ARE EXPECTED TO
REMAIN IN THE 50S DURING THE DAYLIGHT HOURS, ONLY FALLING INTO THE
MID TO UPPER 40S OVERNIGHT WITH THICK CLOUD COVER AND WARM AIR
ADVECTION ALOFT PREVENTING MUCH LOSS OF SURFACE HEATING.
AFTER THE CHRISTMAS EVE/DAY UPPER LEVEL TROUGH MOVES EAST OF
ARKANSAS, SHORTWAVE RIDGING IS EXPECTED TO PROVIDE ABOUT 24 HOURS
OF QUIET WEATHER BEFORE THE NEXT UPPER LEVEL STORM SYSTEM/TROUGH
ARRIVES ON FRIDAY. WITH LITTLE TIME BETWEEN UPPER LEVEL SYSTEMS,
DO NOT EXPECT A SIGNIFICANT CHANCE IN AIRMASS BETWEEN THESE UPPER
LEVEL SYSTEMS AS THE FRONTAL PUSH FROM THE CHRISTMAS UPPER LEVEL
STORM SYSTEM IS EXPECTED TO STALL OUT NORTH OF THE GULF COAST,
ALLOWING FOR RAPID WARM/HUMID AIRMASS RECOVERY BY FRIDAY. A BRIEF
CLEARING OF THE CLOUDS ON THURSDAY IS EXPECTED TO ALLOW
TEMPERATURES TO CLIMB INTO THE UPPER 50S TO LOW 60S ACROSS THE
STATE THURSDAY AFTERNOON. THE RAPID RETURN OF WARM AND HUMID AIR
ADVECTION ALOFT WILL BRING A RAPID ONSET OF CLOUD COVER BACK
ACROSS THE STATE THURSDAY NIGHT KEEPING TEMPERATURES UP IN THE MID
TO UPPER 40S THURSDAY NIGHT INTO FRIDAY MORNING.
BETWEEN WARM AND HUMID AIR ADVECTION THURSDAY NIGHT INTO FRIDAY
AND THE EXPECTED PASSAGE OF ANOTHER UPPER LEVEL TROUGH OVER THE
STATE, WE WILL LIKELY SEE ON AND OFF RAIN SHOWERS ACROSS ARKANSAS
ON FRIDAY. THE SHORTWAVE TROUGH PASSAGE ON FRIDAY IS EXPECTED TO
BE FOLLOWED UP BY A STRONGER UPPER LEVEL TROUGH MOVING OUT OF THE
SOUTHWESTERN CONUS THIS WEEKEND, ALTHOUGH THE TIMING AND STRENGTH
IS A LITTLE LESS CERTAIN GIVEN IT IS 7-8 DAYS OUT IN THE FORECAST
AT THIS TIME. WITH THE POTENTIAL FOR GULF MOISTURE TO ALREADY BE
IN PLACE ACROSS ARKANSAS, THERE IS AT LEAST A LOW/NON-ZERO CHANCE
OF SEEING SOME STRONGER STORMS WITH AT LEAST A LOW-END POTENTIAL
FOR SEVERE THUNDERSTORMS NEXT WEEKEND ACROSS ARKANSAS. WILL NOT
GET TOO DETAILED ON THE POTENTIAL FOR STRONG STORMS NEXT WEEKEND
AT THIS TIME BECAUSE A LOT CAN CHANGE REGARDING THE TIMING AND
STRENGTH OF NEXT WEEKENDS UPPER LEVEL STORM SYSTEM WHICH CURRENTLY
SITS OVER THE NORTHEASTERN FRINGES OF THE EASTERN HEMISPHERE.
CAVANAUGH
AVIATION
(00Z TAFS)
ISSUED AT 543 PM CST FRI DEC 20 2024
HIGH PRESSURE WILL CONTINUE OVER THE AREA THROUGH THE PERIOD. VFR
CONDITIONS WILL CONTINUE.
PRELIMINARY POINT TEMPS/POPS
BATESVILLE AR 25 43 25 47 / 0 0 0 0
CAMDEN AR 27 48 27 53 / 0 0 0 0
HARRISON AR 23 44 26 49 / 0 0 0 0
HOT SPRINGS AR 27 47 27 51 / 0 0 0 0
LITTLE ROCK AR 28 45 28 50 / 0 0 0 0
MONTICELLO AR 29 47 29 53 / 0 0 0 0
MOUNT IDA AR 26 49 26 53 / 0 0 0 0
MOUNTAIN HOME AR 24 42 26 48 / 0 0 0 0
NEWPORT AR 26 42 26 46 / 0 0 0 0
PINE BLUFF AR 27 45 27 51 / 0 0 0 0
RUSSELLVILLE AR 26 47 27 51 / 0 0 0 0
SEARCY AR 26 44 25 48 / 0 0 0 0
STUTTGART AR 28 44 29 49 / 0 0 0 0
LZK WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...99
LONG TERM....99
AVIATION...51
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