990
FXUS63 KOAX 171708
AFDOAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE OMAHA/VALLEY NE
1108 AM CST SUN NOV 17 2024
KEY MESSAGES
- WIDESPREAD RAINFALL IS FORECAST MONDAY INTO MONDAY NIGHT
(90-100% POPS). MANY LOCATIONS WILL SEE AMOUNTS OF 1.0-1.5"
WITH ISOLATED 2"+ READINGS POSSIBLE.
- TURNING WINDY AND COOLER TUESDAY AND WEDNESDAY WITH BELOW-
NORMAL TEMPERATURES LINGERING INTO NEXT WEEKEND.
DISCUSSION
ISSUED AT 356 AM CST SUN NOV 17 2024
TODAY AND TONIGHT...
A VIGOROUS SHORT-WAVE TROUGH CURRENTLY PROGRESSING THROUGH THE
NORTHERN PLAINS AND SOUTHERN MANITOBA WILL CONTINUE EAST WITH
MID-LEVEL HEIGHTS REBOUNDING OVER THOSE SAME LOCATIONS LATER
TODAY. ELSEWHERE, A MID/UPPER-LEVEL LOW OVER THE LOWER CO VALLEY
INTO NORTHERN BAJA AND THE GULF OF CA WILL TRAVERSE NORTHWEST
MEXICO TODAY BEFORE MOVING INTO THE SOUTHERN HIGH PLAINS
TONIGHT. AT THE SURFACE, A COLD FRONT WILL CONTINUE THROUGH
THE REMAINDER OF SOUTHEAST NE AND SOUTHWEST IA EARLY THIS
MORNING AND EVENTUALLY STALL OVER EAST-CENTRAL KS INTO CENTRAL
MO BY THIS EVENING.
LATEST CAM SIMULATED REFLECTIVITY DATA INDICATE THE DEVELOPMENT
OF A LIGHT PRECIPITATION BAND LATER THIS MORNING OVER PORTIONS
OF SOUTHEAST NE AND SOUTHWEST IA. THAT SCENARIO IS SUPPORTED BY
A SMALL AREA OF SHOWERS AND THUNDERSTORMS CURRENTLY MOVING
NORTHEAST THROUGH CENTRAL KS. SIMILAR TO SATURDAY AFTERNOON,
MODEL SOUNDINGS INDICATE A CONSIDERABLE AMOUNT OF DRY AIR IN THE
LOW LEVELS, WHICH COULD LIMIT THE AMOUNT OF PRECIPITATION THAT
REACHES THE GROUND. AS SUCH, THE FORECAST WILL MAINTAIN < 20%
POPS WITH A MENTION OF SPRINKLES.
TEMPERATURES WILL BE COOLER TODAY (BUT STILL ABOVE NORMAL) WITH
HIGHS IN THE 50S.
TONIGHT, THE MASS RESPONSE TO THE ABOVE-MENTIONED SYSTEM MOVING
INTO THE SOUTHERN HIGH PLAINS WILL CONTRIBUTE TO THE DEVELOPMENT
OF A 50-60 MPH LOW-LEVEL JET (LLJ) ACROSS THE SOUTHERN PLAINS.
SIGNIFICANT MOISTURE AND HEAT FLUXES OCCURRING ALONG AND TO THE
NORTH OF LLJ AXIS WILL PROMOTE IN AIR MASS DESTABILIZATION, AND
ISOLATED SHOWERS APPEAR POSSIBLE WITHIN THAT REGIME AS FAR
NORTH AS SOUTHEAST NE TOWARD DAYBREAK MONDAY.
MONDAY AND MONDAY NIGHT...
THE SOUTHERN HIGH PLAINS SYSTEM IS FORECAST TO UNDERGO DEEPENING
AS IT ACCELERATES NORTH-NORTHEAST TO THE VICINITY OF THE NE-KS
BORDER BY MONDAY EVENING, AND MN BY TUESDAY MORNING. WHILE 00Z
ECMWF IS A BIT SLOWER WITH THE MOVEMENT OF THE SYNOPTIC SYSTEM
COMPARED TO THE GFS AND CANADIAN MODELS, THOSE DIFFERENCES
SHOULDN'T AFFECT RAINFALL TOTALS. HOWEVER, THE FASTER
GFS/CANADIAN MODEL SOLUTIONS COULD RESULT IN AMPLE WIND SHEAR
AND FORCING FOR ASCENT COINCIDING WITH A NARROW AXIS OF WEAK,
SURFACE-BASED INSTABILITY, THEREBY SUPPORTING A COMPARATIVELY
GREATER THREAT FOR A STRONG STORM OR TWO OVER SOUTHEAST NE LATE
MONDAY AFTERNOON. THIS REMAINS A LOW-PROBABILITY SCENARIO
(<10% OF OCCURRENCE); HOWEVER, IT'S SOMETHING TO KEEP AN EYE
ON.
THE 00Z HREF INDICATES PEAK RAINFALL RATES (~0.25-0.5"/HR)
BEGINNING IN SOUTHEAST NE AROUND MID-MORNING AND THEN SPREADING
NORTH THROUGH THE AREA WITH DECREASING RATES BY MID TO LATE
AFTERNOON. AS FAR AS RAINFALL AMOUNTS, THE UPDATED FORECAST WILL
BE SIMILAR TO THE PREVIOUS ONE WITH MANY LOCATIONS SEEING
1.0-1.5" WITH ISOLATED TOTALS OF 2" OR MORE. GIVEN THAT SOIL
TEMPERATURES REMAIN ABOVE FREEZING AND ARE RECEPTIVE TO
ADDITIONAL MOISTURE, NO FLOODING IS ANTICIPATED.
THE STRONGEST WINDS (FROM THE SOUTHEAST) ARE EXPECTED AHEAD OF
THE SURFACE LOW OVER SOUTHEAST NE AND SOUTHWEST IA MONDAY
AFTERNOON WHERE GUSTS OF 30-35 MPH ARE POSSIBLE. HIGHS WILL
RANGE FROM AROUND 50 OVER THE NORTHWEST PART OF OUR AREA TO LOW
60S IN FAR SOUTHEAST NE.
THE RAIN WILL END FROM SOUTH TO NORTH MONDAY NIGHT WITH
NORTHWEST WINDS INCREASING TO 15-20 MPH WITH GUSTS OF 25-35 MPH.
TUESDAY AND WEDNESDAY...
THE 00Z MODELS ARE IN FAIRLY GOOD AGREEMENT IN SUGGESTING THAT
THE WEAKENING MONDAY SYNOPTIC SYSTEM WILL BE ABSORBED INTO A
RAPIDLY DEEPENING MID/UPPER-LEVEL LOW OVER THE NORTHERN PLAINS
AND UPPER MS VALLEY REGIONS ON TUESDAY. THAT LOW IS FORECAST TO
UNDERGO FURTHER DEEPENING TUESDAY NIGHT INTO WEDNESDAY WHILE
ADVANCING INTO THE UPPER MIDWEST AND GREAT LAKES. IN THE LOW
LEVELS, A COLD FRONT WILL MOVE THROUGH THE AREA LATE MONDAY
NIGHT OR TUESDAY MORNING WITH WIND GUSTS UP TO 35-40 MPH
FORECAST ACROSS NORTHEAST NE ON TUESDAY. HIGHS ON TUESDAY ARE
EXPECTED TO BE IN THE MID 40S TO LOWER 50S.
A SECONDARY COLD FRONT IS EXPECTED TO MOVE THROUGH THE REGION
TUESDAY NIGHT INTO WEDNESDAY MORNING WITH STRONG POST-FRONTAL
WINDS (FROM THE NORTHWEST ) PERSISTING INTO WEDNESDAY EVENING.
THE 00Z RUN OF THE EPS INDICATES AN 80-100% CHANCE OF WIND GUSTS
>= 34 KTS (39 MPH) ACROSS OUR FORECAST AREA WEDNESDAY,
SUGGESTING A HIGH LIKELIHOOD FOR AT LEAST A WIND ADVISORY. IN
ADDITION TO THE WINDS, THE MODELS INDICATE THE DEVELOPMENT OF A
DEFORMATION SNOW BAND DEVELOPING TUESDAY NIGHT INTO WEDNESDAY
MORNING OVER THE EASTERN DAKOTAS AND MN WITH A FEW FLURRIES
POSSIBLE IN KNOX AND CEDAR COUNTIES AT THAT TIME. HIGHS ON
WEDNESDAY ARE EXPECTED TO RANGE FROM THE UPPER 30S ALONG THE SD
BORDER TO MID 40S IN SOUTHEAST NE.
THURSDAY THROUGH SATURDAY...
THE SYNOPTIC SYSTEM DISCUSSED IN THE PREVIOUS SECTION IS
FORECAST TO CONTINUE EAST, REACHING THE ATLANTIC SEABOARD BY
FRIDAY. AT THE SAME TIME, A MID-LEVEL RIDGE IS EXPECTED TO BUILD
FROM THE THE ROCKIES INTO THE GREAT PLAINS. THAT PATTERN
EVOLUTION WILL SUPPORT A DRY FORECAST WITH BELOW-NORMAL DAYTIME
TEMPERATURES IN THE 40S.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1103 AM CST SUN NOV 17 2024
VFR CONDITIONS WILL PREVAIL THROUGH THE FIRST HALF OF THE TAF
PERIOD, BUT WILL DETERIORATE TO MVFR AND EVENTUALLY IFR/LIFR
BY AROUND 10Z AND BEYOND, AS RAIN MOVES IN FROM SOUTH TO NORTH.
PRIMARILY SHOWERS ARE EXPECTED THROUGH 18Z MONDAY. HOWEVER,
ISOLATED THUNDERSTORMS WILL BE POSSIBLE FROM 18-00Z MONDAY
AFTERNOON/EVENING NEAR KLNK AND KOMA.
OAX WATCHES/WARNINGS/ADVISORIES
NE...NONE.
IA...NONE.
DISCUSSION...MEAD
AVIATION...KG
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