624
FXUS63 KLBF 171129
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
529 AM CST SUN NOV 17 2024
KEY MESSAGES
- SEASONABLE AND SUNNY TODAY WITH SOME GUSTY SOUTHWEST WINDS ACROSS
THE SANDHILLS.
- STORM SYSTEM ARRIVES TOMORROW, BRINGING COOLER TEMPS AND RAIN WITH
THE GREATEST COVERAGE AND AMOUNTS EAST OF HWY 83.
- EVEN COOLER AND MUCH WINDIER TUESDAY INTO WEDNESDAY. WILL NEED TO
MONITOR FOR POTENTIAL HEADLINES.
- GRADUALLY MODERATING TEMPERATURES AND FAIR SKIES TO ROUND OUT
THE WEEK.
SYNOPSIS
ISSUED AT 411 AM CST SUN NOV 17 2024
A CLOSED UPPER LOW NEAR THE BAJA EMBEDDED IN A VERY DEEP WESTERN US
TROUGH COUPLED WITH A NORTHERN PLAINS SHALLOWER TROUGH IS RESULTING
IN HIGHLY AMPLIFIED SOUTHWEST FLOW ALOFT FOR NEBRASKA. THESE TROUGHS
ARE BOUNDED BY A STRONG EAST COAST RIDGE. AT THE SURFACE, A COOL
FRONT IS DRAPED ACROSS THE SOUTHEAST CORNER OF THE STATE, WHILE HIGH
PRESSURE HAS SETTLED INTO THE PANHANDLE. WITH LIGHT TO CALM WINDS IN
PLACE AND CLEAR SKIES OVERHEAD, TEMPERATURES HAVE DROPPED INTO THE
TEENS AT AIA AND LOWER/MID 20S IN THE WESTERN SANDHILLS.
SHORT TERM /THROUGH MONDAY/
ISSUED AT 411 AM CST SUN NOV 17 2024
TODAY AND TONIGHT... THE CENTER OF THE SURFACE HIGH DRIFTS EAST INTO
THE UPPER MISSISSIPPI VALLEY, AND A TROUGH TAKES ITS PLACE ALONG THE
LEE OF THE ROCKIES. SUBSIDENCE WITH THE SURFACE HIGH AND A RIBBON OF
VERY DRY AIR IN THE MID LEVELS WILL KEEP THE SKY MOSTLY CLEAR
THROUGHOUT THE DAY. WINDS WILL INCREASE THOUGH, AS THE SURFACE
PRESSURE GRADIENT TIGHTENS AND H85 FLOW STRENGTHENS. WINDS AT H85
ALSO TRANSITION FROM WESTERLY DOWNSLOPE EARLY IN THE DAY TO
SOUTH/SOUTHWEST LATER ON, HELPING REVERSE THE COOL AIR ADVECTION.
BLENDED IN SOME WARMER GUIDANCE FOR MAX TEMPS, WHICH PLACE THE
VALUES NEAR THE HIGH END OF THE NBM ENVELOPE BUT STILL SOMEWHAT ON
THE LOWER END OF NUMERICAL GUIDANCE. HIGHS RANGE FROM MID 50S
NORTHWEST TO UPPER 50S SOUTHWEST TO AROUND 60 NORTH CENTRAL. LOWS
ALSO TRENDED WARMER, MAINLY IN THE SANDHILLS TOWARD NORTH CENTRAL
NEB, AS LOW LEVEL FLOW BECOMES SOUTHERLY AND SOME MIXING MAY LIMIT
FULL DECOUPLING. CLOUD COVER ALSO INCREASES OVERNIGHT IN THE SOUTH
AS THE PRIMARY UPPER LOW AND SURFACE LOW EJECT ONTO THE PLAINS. THE
ASSOCIATED WARM FRONT SHOULD REMAIN WELL SOUTHEAST OF THE CWA, BUT
AN INVERTED SURFACE TROUGH MAY WORK INTO SOUTHWEST NEB. FOR NOW,
FORECAST LOWS RANGE FROM LOWER 20S PANHANDLE TO LOWER 30S CENTRAL.
TOMORROW... THE DEEP LOW PRESSURE SYSTEM CUTS NORTHEAST TOWARD THE
NE/KS LINE BY EVENING, WHILE A SECONDARY SURFACE LOW APPROACHES FROM
THE NORTHWEST. MOISTURE CONTINUES TO BE A TRICKY ELEMENT AS JUST
ENOUGH DISCREPANCY AMONG THE MODEL SUITE WITH THE LOW TRACK AND THE
SHARP CUTOFF OF HEAVIER PRECIP WILL LIKELY RESULT IN A TIGHT
GRADIENT OF PRECIP COVERAGE AND AMOUNTS. THE GREATEST POTENTIAL FOR
WIDESPREAD CONSISTENT RAIN LIES NEAR AND EAST OF HWY 183, WHILE POP
DROP OFF SIGNIFICANTLY WEST OF HWY 83. ECM EFI SUGGESTS HIGHLY
ANOMALOUS MOISTURE WITH THE SYSTEM WITH GOOD CONFIDENCE AS WELL
(0.8+ AND SOT OF 1+) AS FAR WEST AS HWY 83. NAEFS ENSEMBLES ALSO
SUGGEST HIGHLY ANOMALOUS PWAT WITH VALUES NEAR THE MAX CLIMO, BUT
MOSTLY FOR EASTERN NEB. OVERALL AMOUNTS IN THE NBM REFLECT THIS
PATTERN, RANGING FROM AROUND 0.10" AT LBF-VTN TO 0.25-0.50" AT BBW-
ANW TO 0.75-1.00" AT ONL. MOST SOLUTIONS LOCK ONTO THE AFTERNOON AND
EVENING HOURS FOR THE BULK OF THE PRECIP. OUTSIDE A BRIEF WINDOW AT
THE ONSET OF PRECIP MONDAY MORNING WHERE RAIN-SNOW MIX IS POSSIBLE,
THE MAIN P-TYPE DURING THIS EVENT SHOULD BE RAIN. DESPITE THE UPPER
LOW BEING IN THE VICINITY, THERE IS A DELAY IN THE OVERLY COLD AIR
IN THE THERMAL PROFILE. IN FACT, H85 TEMPS MAINTAIN ABOVE 5C ALL
DAY. CURRENT FORECAST HIGHS RANGE FROM UPPER 40S IN CENTRAL NEB
WHERE THE MORE PERSISTENT RAIN WILL OCCUR TO MID 50S IN THE
PANHANDLE. BY THE TIME TEMPS FALL BACK BELOW FREEZING TOMORROW
NIGHT, THE PRECIP SHOULD HAVE WANED. THE LONE EXCEPTION IS ACROSS
THE FAR NORTHEAST, BUT TEMPS MAY HOLD ABOVE FREEZING.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
ISSUED AT 411 AM CST SUN NOV 17 2024
TOWARD MIDWEEK, THE UPPER LOW GETS ABSORBED INTO THE MAIN NORTHERN
STREAM, BUT A NEW LOW SPINS UP ACROSS THE DAKOTAS. THIS SECONDARY
UPPER LOW WILL BRING A CORE OF COLD AIR AND BLUSTERY WINDS, WHICH IS
PROGGED TO AFFECT THE SANDHILLS TUESDAY INTO WEDNESDAY. THE SURFACE
LOWS MERGE OVER THE UPPER MIDWEST, REINFORCING THE NORTH/NORTHWEST
FLOW FOR NEBRASKA. WIND WILL BE THE MAJOR FACTOR WITH THIS SETUP AS
THE FORECAST AREA EXPERIENCES RAPID SURFACE PRESSURE RISES, A STRONG
PV ANOMALY PASSAGE, AND THE POWERFUL H3 JET NEARBY. GUIDANCE IS IN
GOOD AGREEMENT WITH H85 FLOW PEAKING AROUND 50 KTS EARLY WEDNESDAY
IN THE SANDHILLS. BLENDED IN SOME NBM90 FOR WINDS TO ACCOUNT FOR
THOSE SOLUTIONS AS WELL AS COLLABORATION WITH NEIGHBORING WFOS.
NAEFS/ECM CLIMO SOLUTIONS ALSO SUGGEST ANOMALOUS WINDS AS EFI RANGES
FROM 0.6-0.8 ACROSS THE CWA AND SOT OF 0-1, WHILE H5-85 WINDS REACH
99%ILE OF CLIMO. WILL NEED TO MONITOR FOR POTENTIAL HIGH WIND
HEADLINES, ESPECIALLY WEDNESDAY. MAY ALSO NEED TO KEEP AN EYE OF
FIRE WEATHER AS MINIMUM RH VALUES APPROACH 20% IN THE PANHANDLE.
ANTECEDENT MOISTURE WILL BE SPARSE, AND WITH CURED OR DORMANT FUELS,
THE WIND WILL BE MORE THAN STRONG ENOUGH TO QUICKLY CARRY FLAMES.
CONDITIONS MODERATE LATE WEEK INTO NEXT WEEKEND AS WINDS LIGHTEN AND
TEMPERATURES REBOUND, AT LEAST FOR WESTERN NEB. STEEP NORTHWEST FLOW
WILL HELP KEEP HIGHS COOLER IN THE 40S FOR NORTH CENTRAL NEB, WHILE
WESTERN NEB SHOULD SURPASS 50F AGAIN BY FRIDAY. THE POTENTIAL FOR
ADDITIONAL MOISTURE APPEARS LOW.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 530 AM CST SUN NOV 17 2024
VFR CONDITIONS ARE EXPECTED TO PREVAIL INTO TOMORROW MORNING
ACROSS WESTERN AND NORTH CENTRAL NEBRASKA. GUSTY SOUTHWEST WINDS
ARE EXPECTED ACROSS THE SANDHILLS AND NORTH CENTRAL NEBRASKA
THIS AFTERNOON, WITH GUSTS OF 20 TO 30 KTS EXPECTED. CLOUDS
INCREASE TOWARDS THE END OF THE VALID PERIOD WITH THE APPROACH
OF A STORM SYSTEM, THOUGH SHOULD REMAIN AT LEAST LOW-END VFR
THROUGH EARLY TOMORROW MORNING.
LBF WATCHES/WARNINGS/ADVISORIES
NONE.
SYNOPSIS...SNIVELY
SHORT TERM...SNIVELY
LONG TERM...SNIVELY
AVIATION...BROWN
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