300
FXUS64 KLZK 221739
AFDLZK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LITTLE ROCK AR
1239 PM CDT FRI OCT 22 2021
AVIATION
HIGH PRESSURE WILL CONTINUE OVER THE STATE THIS AFTERNOON. IT WILL
THEN MOVE EAST OF THE AREA TONIGHT AND WINDS WILL BE MORE
SOUTHERLY SATURDAY. INCREASED MOISTURE COMBINED WITH AN UPPER
LEVEL SYSTEM WILL BRING A SLIGHT CHANCE OF SHOWERS INTO THE THE
NORTH PART OF THE STATE IN THE MORNING. VFR CONDITIONS WILL
CONTINUE.
PREV DISCUSSION
(ISSUED 605 AM CDT FRI OCT 22 2021)
AVIATION...
VFR CONDITIONS AND A LIGHT AND VARIABLE SURFACE WIND WILL PREVAIL
TODAY INTO THIS EVENING. MID AND HIGH CLOUDS WILL INCREASE
TONIGHT, ESPECIALLY IN NORTHERN ARKANSAS. (46)
SHORT TERM...TODAY THROUGH SATURDAY NIGHT
THE PERIOD WILL BEGIN WITH HIGH PRESSURE BUILDING OVER THE REGION
TODAY. UNDER THE HIGH, THERE WILL BE PLENTY OF SUNSHINE AND
LIGHT/VARIABLE WINDS. CONDITIONS WILL BE DRY, WITH DEWPOINTS
MOSTLY IN THE 40S.
THE HIGH WILL RETREAT TO THE EAST FRIDAY NIGHT/SATURDAY. RETURN
FLOW WILL CRANK UP MOISTURE LEVELS AND PROVIDE MORE CLOUDS.
DEWPOINTS BY SATURDAY AFTERNOON/EVENING WILL CLIMB INTO THE LOWER
TO MID 60S. ISOLATED TO SCATTERED SHOWERS ARE ALSO EXPECTED IN
PARTS OF NORTHERN ARKANSAS.
BY THE TIME THE PERIOD ENDS, A WARM FRONT WILL PASS THROUGH
THE REGION FROM THE SOUTH, AND IT WILL FEEL MORE LIKE SPRING THAN
FALL. BREEZY SOUTH WINDS WILL DEVELOP, ESPECIALLY IN PARTS OF THE
OZARK MOUNTAINS.
TEMPERATURES WILL BE A LITTLE ABOVE SEASONAL TODAY, AND WELL ABOVE
AVERAGE ON SATURDAY.
LONG TERM...SUNDAY THROUGH THURSDAY
REGARDING THE LONG TERM PD, AN ACTIVE PATTERN WL BE THE MAIN STORY,
AND IN PARTICULAR, INCREASING CONFIDENCE ON A WINDOW OF SVR WX
POTENTIAL FOR PORTIONS OF N/WRN AND NRN AR LATE SUN NIGHT.
SUN, LONG TO MEDIUM RANGE GUIDANCE HAS CONTINUED TO CONVERGE ON THE
EVOLUTION OF A SMALL PERTURBATION INTENSIFYING RAPIDLY UPSTREAM OF
HIGH AMPLITUDE H500 RIDGING OVER THE CNTRL US. A JET STREAK ON THE
UPSTREAM PORTION OF THE INITIAL PERTURBATION IS EXPECTED TO
CONTRIBUTE TO INCREASING DCVA AND H500 HEIGHT FALLS, ALLOWING FOR A
DEEPENING SHORTWAVE TROF TO QUICKLY EJECT OVER THE CNTRL PLAINS SUN
AFTERNOON. ANTECEDENT CYCLONIC SFC FLOW OVER THE PLAINS WL RAPIDLY
DEEPEN INVOF INCREASING DIVERGENCE ALOFT. THROUGH THE DAY SUN, THIS
SFC LOW WL FOLLOW THE MOVEMENT OF THE UPPER SHORTWAVE, TRACKING E/NE
ACROSS KS AND INTO MO. ACROSS THE WARM SECTOR OF THIS SFC LOW,
MOISTURE RETURN IS EXPECTED TO BE VIGOROUS W/ SFC TD'S TOPPING BACK
OUT IN THE MID 60S OVER THE NATURAL STATE. BY SUN EVENING, A
SWEEPING COLD FRNT ASSOCIATED W/ THE SFC LOW WL BE APPROACHING THE
STATE MOVING FROM THE N/W TO THE S/E, AND IS EXPECTED TO BE THE
PRIMARY DRIVER OF THUNDERSTORM ACTIVITY THROUGH THE NIGHT. THE MOST
RECENT SUITE OF 00Z GUIDANCE DEPICTS A FAVORABLE PARAMETER SPACE
OVER THE N/WRN AND NRN PORTION OF AR, PARTICULARLY IN THE 00Z-06Z
TIMEFRAME SUN NIGHT AS THE FRNT ENTERS THE STATE. DESPITE THE
NOCTURNAL TIMING, A WINDOW OF SVR WX POTENTIAL WL BE POSSIBLE FOR
PORTIONS OF N/WRN AND NRN AR LATE SUN NIGHT, AS DEPICTED BY THE NEW
ENH REGION OUTLINED IN THE D3 SPC CONVECTIVE OUTLOOK. ALL SEVERE
HAZARDS WL BE POSSIBLE INCLUDING DAMAGING WINDS AND HAIL, AND
PERHAPS SOME TORNADIC ACTIVITY. SOME CHANGES ARE STILL POSSIBLE TO
THE FCST, SO BE SURE TO STAY UP TO DATE ON THE LATEST HAZARDOUS WX
FCST INFORMATION FROM TRUSTED AND RELIABLE SOURCES.
MON, THE EVOLUTION OF THE AFOREMENTIONED COLD FRNT REMAINS IN
QUESTION B/W THE SOLNS OF THE GFS AND ECMWF, HOWEVER THE CURRENT
BLENDED TEMP FCST CONT TO REFLECT THE GFS SOLN, IN WHICH THE FRNT
STALLS OVER THE STATE, AND PIVOTS FROM A S/W TO N/E STANCE INTO A
MORE W TO E ORIENTATION OVER THE NRN PORTION OF THE FA. AS THE FIRST
SHORTWAVE QUICKLY DEPARTS TO THE N/E, A LONGWAVE TROF OVER THE PAC-
N/W IS EXPECTED TO PROGRESS E/WRD ACROSS THE CONT DIVIDE. A RINSE
AND REPEAT PATTERN WL UNFOLD, W/ ANOTHER STRONG SFC LOW TRACKING E-
N/E OVER KS AND MO, AND ANOTHER TAILING COLD FRNT APPROACHING THE
STATE. WIDESPREAD RAIN AND THUNDERSTORMS ARE ANTICIPATED W/ THIS
NEXT SYSTEM DURING THE TUES/WED TIMEFRAME, HOWEVER MODEL
DISCREPANCIES BECOME MORE ENHANCED AND CONFIDENCE DECREASES
REGARDING SVR WX POTENTIAL...WL CONT TO WATCH THIS SECOND SYSTEM AS
IT NEARS SHORTER RANGE GUIDANCE.
A PRIMARY DIFFERENCE IS APPARENT B/W THE TWO SYSTEMS THOUGH...GIVEN
MUCH STRONGER UPPER-LVL DYNAMICS IN THE SECOND TROF, E.G. A BROADER
LONGWAVE AND GREATER FETCH OF N/WRLY TROPOSPHERIC FLOW, A BIG
COOLDOWN LOOKS TO BE ON THE WAY BY MID-WEEK NEXT WEEK. IN THE WAKE
OF THE COLD FRNT, DIURNAL TRENDS WL RETURN TO MORE SEASONAL VALUES,
ALONG W/ PREVAILING DRY WX AS SFC MOISTURE BOTTOM OUT AND SFC HIGH
PRESSURE SETTLES OVER THE REGION.
LZK WATCHES/WARNINGS/ADVISORIES
NONE.
AVIATION...51
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