420
FXUS64 KJAN 172315 AAA
AFDJAN
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE JACKSON MS
515 PM CST THU JAN 17 2019
UPDATE
UPDATED FOR 00Z AVIATION DISCUSSION
AVIATION
00Z TAF DISCUSSION:
MVFR CONDITIONS AT THE BEGINNING OF THE PERIOD WILL RAPIDLY
DETERIORATE TO IFR DURING THE EVENING AND LIFR IN SPOTS AFTER
MIDNIGHT. THE BROKEN STRATUS DECK IN PLACE WILL QUICKLY FILL IN
ANY HOLES THAT HAVE FORMED THIS AFTERNOON. AFTER THIS OCCURS AND
THE BOUNDARY LAYER BEGINS TO COOL, CEILINGS WILL BEGIN TO LOWER AS
FOG DEVELOPS AT THE SURFACE. A WEAK COLD FRONT WILL MOVE INTO THE
GLH AND GWO AREAS DURING THE LATE EVENING AND MAY SPARE THESE
AREAS THE POOR VISIBILITIES EXPECTED ELSEWHERE. WHILE VISIBILITIES
WILL IMPROVE BY MID TO LATE MORNING FRIDAY, IFR CEILINGS DO NOT
LOOK TO RISE TO MVFR UNTIL THE AFTERNOON./26/
DISCUSSION
THROUGH FRIDAY:
THE WEAK DISTURBANCE MOVING THROUGH THE REGION TODAY HAS HELPED KEEP
THE REGION CLOUDY WITH PATCHES OF DRIZZLE AND LIGHT SHOWERS
PROLONGING THE DAMPNESS. DESPITE THE CLOUDS, WARM AIR ADVECTION IN
THE ATMOSPHERIC LOWER LEVELS HAS BEEN GRADUALLY RAISING TEMPERATURES
WITH SOME LOCATIONS ACROSS SOUTHERN MS AND WEST OF THE MS RIVER
LIKELY ACHIEVING THE 60 DEGREE MARK THIS AFTERNOON. BUT THIS SUBTLE
WARMTH AND MOISTURE ADVECTION WILL ALSO ENSURE LOW CLOUDS CONTINUE
INTO TONIGHT AHEAD OF A WEAK APPROACHING COLD FRONT THAT IS EXPECTED
TO DROP INTO THE ARKLAMISS DELTA BEFORE STALLING. ANY FURTHER RAIN
TONIGHT WILL GENERALLY BE LIMITED TO PATCHY LIGHT DRIZZLE AS THE
INCOMING AND STALLING FRONT WILL LACK UPPER SUPPORT AND LIFT FOR
MORE SIGNIFICANT PRECIPITATION. THE MAIN CONCERN FOR LATER TONIGHT
(AND LASTING INTO AT LEAST TOMORROW MORNING) WILL BE DENSE FOG.
CONFIDENCE AT THIS JUNCTURE IS HIGH THAT AREAS OF FOG WILL GRADUALLY
BECOME WIDESPREAD THROUGH THE NIGHT DUE TO A COMBINATION OF SUBTLE
MOISTURE ADVECTION AT THE SURFACE AND COOL GROUND AIDING IN "BUILD-
DOWN" OF LOW STRATUS TOWARD THE SURFACE. HOWEVER, AT THIS TIME
CONFIDENCE IS NOT HIGH THAT FOG WILL BE TRULY DENSE ON A WIDESPREAD
ENOUGH BASIS TO WARRANT ISSUANCE OF A DENSE FOG ADVISORY. SO, FOR
NOW, WE WILL MENTION PATCHY DENSE FOG CONCERNS IN THE HWO AND
GRAPHICS FOR TONIGHT AND THE ONCOMING SHIFT WILL MONITOR THE
SITUATION CLOSELY.
OTHERWISE, EXPECT LOWS REMAINING IN THE RELATIVELY MILD UPPER 40S TO
LOWER 50S. TOMORROW, LOW LEVEL WARMTH AND MOISTURE ADVECTION WILL
CONTINUE AND SHOULD FINALLY DELIVER WIDESPREAD HIGHS IN THE 60S BY
THE AFTERNOON. IT IS NOT OUT OF THE QUESTION LOCATIONS ALONG AND
SOUTH OF THE I-20 CORRIDOR MAY MAKE A RUN AT 70 DEGREES IF A DECENT
AMOUNT OF SUNSHINE PREVAILS BY THE AFTERNOON HOURS. HOWEVER, GIVEN
RECENT HISTORY OF MUCH MORE CLOUDS THAN SUN, IT IS HARD TO NOT BE
BIASED ON CLOUDS BEING DOGGED ACROSS MUCH OF THE AREA TOMORROW. IT
IS ALSO EASIER TO HAVE THIS STANCE WHEN MUCH OF THE GUIDANCE IS
SUGGESTING FOG MAY NOT BREAK UP IN MANY LOCATIONS TOMORROW UNTIL THE
LATE MORNING TO MIDDAY TIME WINDOW. REGARDLESS, AT LEAST ANY RAIN
DURING THE DAY TOMORROW SHOULD BE LIMITED TO VERY PATCHY AND LIGHT
DRIZZLE IN THE MORNING WITH PRECIPITATION ASSOCIATED WITH THE NEXT
SYSTEM HOLDING OFF UNTIL TOMORROW NIGHT. /BB/
FRIDAY NIGHT THROUGH SATURDAY: A ROBUST AND QUICK MOVING STORM
SYSTEM WILL TRACK FROM THE RED RIVER VALLEY FRIDAY NIGHT INTO THE
MIDSOUTH BY SATURDAY MORNING, BRINGING A COLD FRONT ACROSS THE
AREA EARLY IN THE DAY. SHOWERS WILL BEGIN TO INCREASE FRIDAY
EVENING, WITH GREATER RAIN CHANCES AND A FEW STORMS POSSIBLE
OVERNIGHT. WITH A POTENT LOW LEVEL JET AND STRONG DEEP LAYER SHEAR
TRAVERSING THE REGION AND WEAK INSTABILITY DEVELOPING AHEAD OF
THE FRONT, A FEW SEVERE STORMS CAN'T BE RULED OUT MAINLY JUST
AHEAD OF THE FRONT. MODELS HAVE BEEN TRENDING FASTER WITH THIS
SYSTEM, AND THE LIMITED WINDOW OF SEVERE WEATHER THREAT IS
EXPECTED TO CLOSE BY THE AFTERNOON IN MOST AREAS. OF COURSE, THE
MORNING TIMING IS NOT GENERALLY FAVORABLE FOR A SIGNIFICANT UPTICK
IN INSTABILITY. WE'LL CONTINUE TO ADVERTISE THE MARGINAL RISK FOR
SEVERE STORMS IN THE HWO/GRAPHICS. ONE OTHER HAZARD WE WILL HAVE
TO KEEP IN MIND IS THE GRADIENT WIND THREAT GIVEN FORECAST 925 MB
WINDS IN THE 40-50 KT RANGE WITH THE SURFACE LOW PASSING CLOSE TO
THE AREA. LATER SHIFTS MAY NEED TO INCLUDE THE WIND THREAT IN THE
HWO. LIMITED WRAP AROUND SHOWER ACTIVITY WILL LINGER INTO THE
AFTERNOON AND EVENING MAINLY ACROSS NORTHERN AND EASTERN PORTIONS
OF THE AREA. IT WILL TURN SHARPLY COLDER BEHIND THE FRONT, AND
FORECAST THERMAL PROFILES SUGGEST LIGHT RAIN COULD BRIEFLY MIX
WITH OR CHANGE TO LIGHT SNOW ALONG THE HWY 82 CORRIDOR BEFORE
ENDING SATURDAY NIGHT. HOWEVER, NO ACCUMULATIONS OR TRAVEL ISSUES
ARE ANTICIPATED IN OUR AREA. MOST PRECIPITATION IS EXPECTED TO BE
GONE BEFORE MIDNIGHT.
SUNDAY AND MONDAY: THE NEW WEEK WILL GET OFF TO A BLUSTERY START.
THOUGH PRECIP WILL BE CLEAR OF THE AREA, LOW CLOUDS MAY LINGER
INTO AT LEAST A PORTION OF THE DAYTIME SUNDAY. AFTER A BREEZY AND
COLD MORNING WITH WIND CHILLS POSSIBLY IN THE 20S (TEENS POSSIBLE
IN THE DELTA), TEMPS AREN'T EXPECTED TO GET OUT OF THE 30S IN
NORTH MS. WITH WINDS DROPPING OFF DURING THE EVENING, IF THERE IS
SUFFICIENT CLEARING WE COULD SEE STRONG RADIATIONAL COOLING
SUNDAY NIGHT/MONDAY MORNING WITH TEMPS GETTING WELL INTO THE 20S
ACROSS MOST OF THE AREA. AS SURFACE FLOW QUICKLY TURNS BACK
AROUND, CONDITIONS WILL BEGIN TO MODERATE AGAIN MONDAY. THE BREAK
IN THE RAIN CHANCES WILL BE FLEETING, HOWEVER, AS THE PATTERN
REMAINS QUITE PROGRESSIVE.
TUESDAY THROUGH NEXT THURSDAY: ANOTHER SHARP MID/UPPER TROUGH
WILL BRING A RESURGENCE OF SHOWER ACTIVITY AS EARLY AS THE
DAYTIME HOURS TUESDAY, WITH GREATER RAIN CHANCES AS ANOTHER COLD
FRONT MOVES INTO THE AREA TUESDAY NIGHT. WITH A MORE LIMITED
WINDOW FOR MOISTURE/INSTABILITY RECOVERY AHEAD OF THIS SYSTEM,
WE'RE NOT ANTICIPATING THUNDER AT THIS TIME. THERE REMAINS SOME
MODEL DISAGREEMENT ON EXACTLY HOW THIS SYSTEM WILL EVOLVE, WITH
THE GFS SUGGESTING A LESS PROGRESSIVE SURFACE FRONT/WAVE AND THE
POTENTIAL FOR COLDER AIR TO "CATCH UP" WITH THE SYSTEM AND A
POSSIBLE TRANSITION IN PRECIP TYPE ON THE BACK END.
CLIMATALOGICALLY, THIS IS NOT A TYPICAL SETUP FOR NOTABLE WINTRY
PRECIP IN OUR AREA, AND GIVEN THE DISAGREEMENT WITH THE EURO
SOLUTION, WE'LL CONTINUE TO LEAVE OUT ANY MENTION OF WINTRY
WEATHER FOR THIS PORTION OF THE FORECAST.
DRIER AND COOLER WEATHER IS ANTICIPATED NEXT THURSDAY. CLOUDS MAY
LINGER THROUGH THE DAY AS WE REMAIN UNDER THE AXIS OF A LONGWAVE
UPPER TROUGH. /DL/
PRELIMINARY POINT TEMPS/POPS
JACKSON 50 65 57 65 / 34 8 79 87
MERIDIAN 49 64 56 68 / 36 10 52 90
VICKSBURG 49 66 58 64 / 19 9 91 77
HATTIESBURG 51 67 58 68 / 28 11 50 86
NATCHEZ 50 67 59 64 / 17 9 88 77
GREENVILLE 46 61 56 60 / 21 8 96 75
GREENWOOD 48 62 56 63 / 26 8 91 88
JAN WATCHES/WARNINGS/ADVISORIES
MS...NONE.
LA...NONE.
AR...NONE.
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