143
FXUS64 KLZK 280535 AAA
AFDLZK
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LITTLE ROCK AR
1135 PM CST SAT FEB 27 2021
AVIATION
UPDATED W/ A DISCUSSION FOR THE 28/06Z TAFS
A WARM FRNT IS CURRENTLY SITUATED OVER SRN AR BUT CONT TO MOVE
N/WRD VERY SLOWLY. SHRA WILL PERIODICALLY DEVELOP INVOF THE FRNT
THROUGH THE OVERNIGHT PD...RADAR IMGRY INDICATED MORE SHRA HAD
BEGUN OVER S/WRN AR INVOF HOT/ADF. DENSE FG WILL CONT THROUGH THE
EARLY PART OF THE PD AS THE FRNT MOVES N/WRD WITH SEVERELY REDUCED
VIS/CIGS. A COLD FRNT WILL MOVE INTO N/W AR SUN AFTERNOON AND SCT
SHRA/TSRA ARE EXPECTED ALONG THE FRNT. LLWS WILL ALSO BE
PREVALENT OVER MUCH OF THE FCST AREA DURING THE FIRST HALF OF THE
PD. VLIFR/LIFR CONDNS WILL CONT THROUGH THE FIRST HALF OF THE PD,
W/ CIGS AND VIS IMPROVING TO MVFR LEVELS BY SUN AFTERNOON.
/232/
PREV DISCUSSION...(ISSUED 244 PM CST SAT FEB 27 2021)
SHORT TERM...TODAY THROUGH MONDAY
SEVERAL NOTABLE WEATHER FEATURES CAN BE DEPICTED ACROSS THE
CNTRL/SRN CONUS VIA MSAS, SATELLITE, AND RADAR DATA THIS
AFTERNOON. SURFACE LOW PRESSURE IS SITUATED OVER SWRN KS WITH A
SURFACE WARM FRONT DRAPED TO THE S AND E ACROSS THE ARKLATEX TO
ARKLAMISS REGION AND POINTS FURTHER EWRD INTO THE TN VALLEY. TO
THE S OF THE WARM FRONT, TEMPERATURES HAVE CLIMBED WELL INTO THE
70S ON SRLY WINDS, WHEREAS N OF THE FRONT, TEMPERATURES HAVE
LARGELY REMAINED STEADY IN THE 50S WITH PATCHY AREAS OF FOG/LOW
STRATUS LOCKED IN BELOW A TEMPERATURE INVERSION AND ERLY WINDS.
RECENT RADAR TRENDS INDICATE A THIN RIBBON OF CONVECTION JUST TO
THE N OF THE SURFACE FRONT, ~H925-H850 LAYER, WHERE WAA/ISENTROPIC
ASCENT IS NOW PROMOTING PRECIPITATION INITIATION.
THIS ACTIVITY IS EXPECTED TO LIFT NWRD THIS AFTERNOON AND GROW
UPSCALE AS THE WARM FRONT ADVANCES INTO SRN THEN CNTRL AR BY THIS
EVENING. A FEW OF THESE STORMS COULD BECOME LOCALLY STRONG TO
MARGINALLY SEVERE WITH LARGE HAIL THE PRIMARY HAZARD. GIVEN A STRONG
LOW-LEVEL INVERSION OVER THIS PORTION OF THE STATE, CONVECTION WILL
BE ELEVATED THEREFORE REDUCING THE CHANCES FOR DAMAGING WINDS.
TEMPERATURES DURING THE OVERNIGHT PERIOD WILL ACTUALLY WARM AS
WAA OVERSPREADS THE REGION. FOG IS EXPECTED TO REDEVELOP TO THE N
OF THE WARM FRONT AS MOIST AIR ADVECTS INTO AREAS OF COOLER
TEMPERATURES. THE FOG MAY BE BECOME DENSE AT TIMES BUT SHOULD
DECREASE IN INTENSITY OVERNIGHT AS WARMER AIR WORKS INTO THE
REGION. BY DAYBREAK, THE MAJORITY OF THE FOG IS EXPECTED TO BE
OVER NRN AR AND SOME VALLEY LOCATIONS OF THE OZARKS AND OUACHITAS.
SUNDAY, THE AFOREMENTIONED WARM FRONT WILL STALL TO OUR N BEFORE
BEING PICKED UP BY AN APPROACHING UPPER SYSTEM AND REDIRECTED TO THE
S AND E AS A COLD FRONT. ADDITIONAL CONVECTION IS EXPECTED TO
DEVELOP BENEATH CYCLONIC FLOW DOWNSTREAM OF AN APPROACHING UPPER
TROUGH. SUFFICIENT PWS WILL BE PRESENT THANKS TO GULF MOISTURE
CONFLUENCE WITH MOISTURE FROM THE PINEAPPLE EXPRESS. RAINFALL MAY
BECOME HEAVY AT TIMES LEADING TO POCKETS OF FLASH FLOODING. STORM
MOTIONS WILL BE NEARLY PARALLEL TO THE UPPER STEERING FLOW WHICH
WILL AID IN HEAVIER RAINFALL TOTALS. CURRENT FORECAST HAS
WIDESPREAD 1 TO 3 INCHES OF ADDITIONAL RAIN POSSIBLE S AND E OF
THE I-30/HWY 67/167 CORRIDOR WITH AMOUNTS FALLING OFF FURTHER N
AND W. EVENTUALLY THE APPROACHING TROUGH WILL EJECT THE FIRST
SYSTEM AND COLD FRONT, BRINGING DRIER CONDITIONS TO MUCH OF AR.
WITH THE UPPER FLOW REMAINING OUT OF THE SW, THE SYSTEM WILL
BECOME STATIONARY AGAIN OVER N LA/SRN AR INTO MONDAY. A SMALL
PIECE OF ENERGY IS PROGGED TO BREAK OFF THE UPPER FLOW, BECOMING A
CLOSED LOW, WHICH WILL SERVE TO ENHANCE RAIN CHANCES THROUGH THE
SHORT TERM AS THE SYSTEM MEANDERS TOWARDS THE REGION BY MONDAY
NIGHT.
LONG TERM...MONDAY NIGHT THROUGH SATURDAY
IT HAS BEEN SEVERAL DAYS SINCE THIS HAS OCCURRED BUT THE MEDIUM
RANGE MODELS ARE ACTUALLY COMING INTO BETTER AGREEMENT IN THE LONG
TERM PERIOD, AT LEAST INITIALLY, BEFORE DIVERGING ONCE AGAIN. THE
KEY PHRASE HERE IS BETTER AND MANY DIFFERENCES CONTINUE IN THE FINER
DETAILS BUT ON A SYNOPTIC SCALE THE ECMWF AND GFS ARE IN GOOD ENOUGH
AGREEMENT THAT A BLEND OF MODEL SOLUTIONS IS PREFERRED THIS
AFTERNOON.
PERIOD INITIATES WITH THE PROGRESSIVE PATTERN REMAINING IN PLACE.
THE PERSISTENT UPPER RIDGE OVER THE CARIBBEAN WILL REMAIN IN PLACE
WITH YET ANOTHER UPPER LOW COMING OUT OF THE WEST AND MOVING ALONG
THE RED RIVER/TX PANHANDLE REGION. MODELS SUGGEST THAT THE FRONT
THAT HAS PLAGUED THE AREA OF LATE WILL BE LOCATED ALONG THE GULF
COAST WITH A SURFACE LOW MOVING ALONG IT. THIS WILL RESULT IN
ADDITIONAL RAIN CHANCES FOR CENTRAL AND ESPECIALLY SOUTHERN PARTS OF
THE STATE MONDAY NIGHT AND TUESDAY AS THE UPPER LOW MOVES ACROSS.
MODELS SUGGEST THAT THE HEAVIEST QPF WILL STAY SOUTH OF THE STATE
BUT ANOTHER QUARTER TO HALF INCH OF RAIN COULD FALL OVER THE SOUTH
MONDAY NIGHT AND TUESDAY. TEMPERATURES WILL BE BORDERLINE ACROSS THE
NORTH FOR A BRIEF RAIN/SNOW MIX LATE MONDAY NIGHT/TUESDAY MORNING.
NO ACCUMULATION OR IMPACTS ARE EXPECTED. THIS SYSTEM WILL CLEAR THE
REGION TUESDAY EVENING WITH WEAK RIDGING ACTUALLY PROVIDING A DRY
WEDNESDAY.
NEXT SOUTHERN STREAM SYSTEM WILL ROLL IN LATE THURSDAY AND INTO
FRIDAY TO BRING ADDITIONAL RAIN CHANCES TO THE AREA. HERE IS WHERE
SOME OF THOSE DIFFERENCES BETWEEN THE MODELS SHOW UP AGAIN WITH THE
GFS HAVING THE UPPER LOW ALONG THE ARKANSAS/LOUISIANA BORDER AND THE
ECMWF PLACING IT OVER CENTRAL OKLAHOMA. AS SUCH, A GENERAL BROAD
BRUSH WILL BE USED FOR PRECIP CHANCES LATE IN THE PERIOD WITH A WAIT
AND SEE APPROACH BEING TAKEN.
TUESDAY APPEARS TO BE THE COOLEST DAY IN THE LONG TERM WITH OVERALL
TEMPERATURES AVERAGING AROUND 5 TO 8 DEGREES BELOW NORMAL. STARTING
ON WEDNESDAY AND THROUGH THE REMAINDER OF THE PERIOD, TEMPERATURES
LOOK TO AVERAGE ABOUT 5 DEGREES ABOVE NORMAL.
LZK WATCHES/WARNINGS/ADVISORIES
DENSE FOG ADVISORY UNTIL 9 AM CST SUNDAY FOR ARKANSAS-BAXTER-
BOONE-BRADLEY-CALHOUN-CLARK-CLEBURNE-CLEVELAND-CONWAY-DALLAS-
DESHA-DREW-FAULKNER-FULTON-GARLAND-GRANT-HOT SPRING-INDEPENDENCE-
IZARD-JACKSON-JEFFERSON-JOHNSON-LAWRENCE-LINCOLN-LOGAN-LONOKE-
MARION-MONROE-MONTGOMERY-NEWTON-OUACHITA-PERRY-PIKE-POLK-POPE-
PRAIRIE-PULASKI-RANDOLPH-SALINE-SCOTT-SEARCY-SHARP-STONE-VAN
BUREN-WHITE-WOODRUFF-YELL.
FLOOD WATCH FROM 6 AM CST SUNDAY THROUGH LATE SUNDAY NIGHT FOR
ARKANSAS-BRADLEY-CALHOUN-CLEVELAND-DESHA-DREW-JEFFERSON-LINCOLN-
LONOKE-MONROE-PRAIRIE-WOODRUFF.
AVIATION...GREEN
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