842
FXUS63 KLBF 182350
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
650 PM CDT FRI OCT 18 2024
KEY MESSAGES
- INCREASING RAIN AND THUNDERSTORM CHANCES FOR TONIGHT THROUGH SATURDAY
WITH POTENTIAL FOR LOCALLY HEAVY RAIN TOTALS (1-2").
- ANOTHER ROUND OF RAIN POSSIBLE SUNDAY NIGHT INTO MONDAY AS AN UPPER-
LEVEL DISTURBANCE PASSES.
- OVERALL WEATHER PATTERN NEXT WEEK FAVORS ABOVE NORMAL
TEMPERATURES AND DRY WEATHER AGAIN THOUGH BRIEF COOL DOWNS
ARE POSSIBLE AS FRONTAL BOUNDARIES PASS THROUGH.
SHORT TERM /THROUGH SATURDAY/
ISSUED AT 300 PM CDT FRI OCT 18 2024
EARLY AFTERNOON SATELLITE ANALYSIS DEPICTS A MID-LEVEL DISTURBANCE
SLOWLY TRACKING ACROSS THE DESERT SOUTHWEST. AHEAD OF THIS FEATURE,
A PLUME OF INCREASED MOISTURE IS RIDING UP AND OVER DOWNSTREAM
RIDGING CENTERED ON THE UPPER OHIO RIVER VALLEY. ANOTHER DISTURBANCE
IS BEGINNING TO ENCROACH ON THE PACIFIC NORTHWEST ASSOCIATED WITH A
DEEPER LOW ACROSS THE GULF OF ALASKA.
TODAY, DEEP LOW-PRESSURE UP INVOF THE HUDSON BAY WILL CONTINUE TO
SHUFFLE EAST. AN ATTENDANT COLD FRONT EXTENDS SOUTH ACROSS THE UPPER
MIDWEST AND INTO THE CENTRAL PLAINS. AS OF 19Z, THIS FEATURE WILL
SITUATED JUST SOUTH OF AN IMPERIAL TO AINSWORTH LINE. AHEAD OF THIS,
MOISTURE CONTINUES TO POOL AS DEW POINTS HAVE CLIMBED INTO THE UPPER
40S IN MODERATE SOUTHERLY FLOW. UPSTREAM OBSERVATIONS SHOW LOW 50S
DEW POINTS IN NORTHWEST KANSAS AND EXPECTATIONS ARE FOR THIS
MOISTURE TONGUE TO NOSE INTO SOUTHWEST AND SOUTH CENTRAL NEBRASKA
LATE THIS AFTERNOON AND EARLY THIS EVENING. WHILE MODEST LAPSE RATES
ARE ALREADY IN PLACE EARLY TODAY, GUIDANCE SUGGESTS THESE WILL WANE
OVER THE NEXT 12 HOURS. THE INCREASING MOISTURE QUALITY MAY OVERLAP
ENOUGH WITH THE LAPSE RATES ALOFT TO PROMOTE MODERATE BUOYANCY.
LATEST RAP GUIDANCE SUGGESTS POTENTIAL FOR EVEN NEAR 1000 J/KG OF
SBCAPE ACROSS OUR FAR SOUTHWEST ZONES. SHEAR ALOFT IS PLENTIFUL AS
H5 FLOW REMAINS ELEVATED AROUND 30 TO 40 KNOTS. EVEN WITH SOUTHERLY
FLOW IN THE WARM SECTOR, THIS SHOULD SUPPORT DEEP-LAYER SHEAR
MAGNITUDES AROUND 20 TO 30 KNOTS. WORKING AGAINST THIS, HOWEVER,
WILL BE SHEAR VECTORS PARALLEL TO THE DRAPED SURFACE FRONT. THIS
SUGGESTS QUICK UPSCALE GROWTH AND LATEST HRRR RUNS ADVERTISE AS MUCH
BEYOND THE FIRST HOUR OR TWO OF INITIATION. STORM MOTIONS SHOULD
CARRY STORMS ACROSS THE BOUNDARY AND ONTO THE COOL SIDE WHERE
INSTABILITY WILL BE NEARLY NEGLIGIBLE AND SO ANY STORM THREAT SHOULD
QUICKLY DIE OFF AS THIS OCCURS. STILL THOUGH, CAN'T RULE OUT SOME
SMALLER HAIL AND GUSTY WINDS IN STRONGER CORES BUT SEVERE WEATHER IS
NOT EXPECTED AT THIS TIME. WHAT IS MORE CONCERNING IS QUICK UPSCALE
GROWTH OF TRAINING THUNDERSTORMS MAY LEAD TO LOCALIZED HEAVY RAIN.
WHILE I TRY TO USE THAT PHRASE LIGHTLY IN THE STEADILY INCREASING
DROUGHT CONDITIONS, CONSECUTIVE RUNS OF HI-RES GUIDANCE CONTINUES TO
PAINT INCREASING QPF IN LOCALIZED AREAS NEAR IF NOT JUST BEHIND THE
BOUNDARY. FORECAST SOUNDINGS SHOW GOOD SATURATION THROUGH THE
PROFILE AND SKINNY CAPE PROFILES WITHIN ANOMALOUS PWAT VALUES. THE
12Z UPPER AIR SOUNDING FROM LBF SAMPLED 0.90" PWATS OR GREATER THAN
150% OF NORMAL. THOUGH STORM MOTION AND UPWIND PROPAGATION VECTORS
SUGGEST PROGRESSIVE STORMS, THE TRAINING THREAT IS WHAT IS NECESSARY
TO MONITOR. AS MENTIONED, RECENT HRRR RUNS ARE NOW ADVERTISING 1-2"
OF RAIN THROUGH EARLY MORNING SATURDAY STRETCHING FROM SOUTHWEST
NEBRASKA UP INTO THE CENTRAL SANDHILLS. LATEST QPF CLOSELY MATCHES
HREF PROBABILITY-MATCHED MEAN VALUES WITH A SLIGHT MAXIMA FROM CHASE
COUNTY UP THROUGH SOUTHERN BROWN COUNTY WHERE AMOUNTS LIKELY EXCEED
0.50". ELSEWHERE, MOST LOCATIONS SHOULD REMAIN AT OR BELOW 0.25".
THESE PEAK VALUES MAY FALL SHORT OF WHAT OCCURS THOUGH THERE REMAINS
ENOUGH UNCERTAINTY IN WHERE THE NARROW 20 MILE BAND SETS UP. WILL
ADVISE SUBSEQUENT SHIFTS TO CLOSELY MONITOR THROUGH LATE THIS
AFTERNOON.
TONIGHT, AS INSTABILITY WANES, STORM STRENGTH SHOULD CLOSELY FOLLOW
AND LEAD TO SCATTERED AND WIDESPREAD GENERAL THUNDERSTORMS. THIS
ACTIVITY WILL BE PROPELLED BY AN INCREASING LLJ AND MODEST WAA.
CONVERGENCE ALONG THE H85 FRONT WILL ALSO REMAIN STRONG AND AS A
RESULT FGEN BE A MAIN DRIVER. GRADUAL WEAKENING OF THIS IS FORECAST
THE CLOSER TO DAYBREAK ON SATURDAY WE GET AND AS SUCH COVERAGE AND
INTENSITY OF RAINFALL SHOULD DECREASE. MAINTAINED CHANCE (< 30%)
POPS ACROSS OUR SOUTHERN ZONES THROUGH THE OVERNIGHT WITH DRY
CONDITIONS LIKELY RETURNING FOR MOST IF NOT ALL LOCATIONS NORTH OF I-
80. LOWS AS A RESULT WILL VARY CONSIDERABLY WITH LOW 30S IN OUR
NORTHWEST AND UPPER 40S TO LOWER 50S FOR OUR SOUTH AND EAST ZONES.
DRY CONDITIONS RETURN TO THE WHOLE OF THE FORECAST AREA ON SATURDAY
AS THE SURFACE BOUNDARY CONTINUES TO SLOWLY SETTLE SOUTH. MID-LEVEL
HEIGHT RISES AS SHORTWAVE RIDGING BUILDS WILL LIKELY SQUASH ANY
AFTERNOON PRECIPITATION POTENTIAL. DID BOOST AFTERNOON HIGHS
SLIGHTLY ALONG OUR FAR EASTERN ZONES AS THE FRONTAL BOUNDARY MAY
STALL IN THIS IMMEDIATE VICINITY. EVEN STILL, ENCROACHING HIGH
PRESSURE SHOULD ALLOW FOR MUCH COOLER TEMPERATURES WITH MANY
LOCATIONS LIKELY HANGING ONTO THE 60. ONLY A FEW LOCATIONS NEAR THE
BOUNDARY ARE LIKELY TO EXCEED THAT, PERHAPS INTO THE LOW TO MIDDLE
70S.
LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/
ISSUED AT 300 PM CDT FRI OCT 18 2024
SUNDAY AND MONDAY...OUR NEXT POTENTIAL FOR RAIN. SHORTWAVE RIDGING
WILL BREAKDOWN AS THE DEEP LOW CURRENTLY ACROSS THE DESERT SOUTHWEST
BEGINS TO TRACK ACROSS THE CENTRAL ROCKIES. BROAD WAA AHEAD OF
APPROACHING H5 LOW WILL USHER WARMER TEMPERATURES AS A WARM FRONT
LIFTS NORTH. AFTERNOON HIGHS ON SUNDAY WILL RETURN TO THE 70S TO
NEAR 80 WITH BREEZY SOUTH WINDS. INCREASING LOW-LEVEL MOISTURE WITH
DEW POINTS CLIMBING BACK INTO THE 50S WILL OFFSET ANY FIRE CONCERNS
AT THIS TIME. MEAGER LAPSE RATES ALOFT SHOULD LIMIT ANY THREAT FOR
SEVERE WEATHER WITH GENERAL THUNDERSTORMS EXPECTED. THIS ACTIVITY
WOULD FAVOR THE HIGHER TERRAIN BEFORE MOVING IN LATE SUNDAY INTO
EARLY MONDAY. IN FACT, SOME GUIDANCE SUGGESTS MOST IF NOT ALL
ACTIVITY HOLDS OFF UNTIL EARLY MONDAY. WILL KEEP SLIGHT CHANCE POPS
(< 20%) TO ACCOUNT FOR THE LIMITED CONFIDENCE SUNDAY EVENING,
INCREASING TO CHANCE (UP TO 50%) MONDAY. MAIN H5 LOW LOOKS TO TRACK
IMMEDIATELY OVERHEAD WITH MANY DETERMINISTIC SOLUTIONS ADVERTISING
AS MUCH. THIS SHOULD ALLOW FOR ENOUGH DRY AIR INTRUSION TO LIMIT
PRECIPITATION POTENTIAL AND LEAD TO A SWIFT END WEST TO EAST DURING
THE LATTER HALF OF MONDAY. ANOTHER DAY OF COOLER TEMPERATURES IS
LIKELY THANKS TO PRECIPITATION AND CLOUD COVER WITH FORECAST HIGHS
IN THE 60S TO LOW 70S.
TUESDAY AND BEYOND...FOLLOWING THE DEPARTURE OF THE SUNDAY/MONDAY
SYSTEM, THE EXTENDED PERIOD BECOMES MORE TAME ONCE AGAIN. A DEEPER
SYSTEM WITHIN THE NORTHERN STREAM WILL DIVE SOUTHEAST INTO THE GREAT
LAKES AROUND THE MIDDLE OF THE WEEK. THIS WILL DRAG A COLD FRONT
SOUTH AND INTO THE LOCAL AREA SOMETIME LATE TUESDAY INTO EARLY
WEDNESDAY. THE INHERITED MODEL BLEND POPS HAVE PAINTED SLIGHT CHANCE
AND CHANCE (UP TO 25%) CATEGORIES FOR AREAS NORTH OF INTERSTATE 80.
DETERMINISTIC AND ENSEMBLE GUIDANCE VARIES CONSIDERABLY ABOUT THIS
POTENTIAL WITH THE GFS AND GEFS SUGGESTING A DRY FORECAST WHILE THE
ECMWF AND EPS ADVERTISING AT LEAST LIGHT QPF IN THESE AREAS. THIS
WILL NEED MONITORED GOING FORWARD. WHAT IS MORE PROBABLE IS COOLER
TEMPERATURES FOR A DAY OR SO IN THE POST-FRONTAL AIRMASS. RIDGING
LOOKS TO REDEVELOP AS RIDGE AXIS APPEARS LIKELY TO SETTLE EITHER
ACROSS THE CENTRAL PLAINS IF NOT IMMEDIATELY UPSTREAM. THIS WILL
SUPPORT MODERATING TEMPERATURES WITH HIGHS RETURNING TO THE 70S OR
NEARLY 20 DEGREES ABOVE NORMAL FOR LATE OCTOBER. THIS MATCHES LATEST
CLIMATE PREDICTION CENTER OUTLOOKS AND NAEFS 8-14 DAY MEAN
OUTPUTS.
AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 637 PM CDT FRI OCT 18 2024
SCATTERED RAIN SHOWERS AND EVEN A FEW ISOLATED EMBEDDED
THUNDERSTORMS WILL BE POSSIBLE THIS EVENING INTO TONIGHT ACROSS
WESTERN, SOUTHWEST AND NORTH CENTRAL NEBRASKA, INCLUDING KVTN
AND KLBF TERMINALS. CIGS WILL LOWER TONIGHT WITH MVFR TO IFR
CONDITIONS POSSIBLE ACROSS PARTS OF THE SANDHILLS INTO SOUTHWEST
NEBRASKA, INCLUDING KLBF TERMINAL. CIGS WILL LIFT BY EARLY
AFTERNOON AND VFR CONDITIONS ARE EXPECTED. WINDS ACROSS SOUTHERN
NEBRASKA WILL CONTINUE TO SWITCH FROM THE SOUTH TO THE NORTHWEST
THIS EVENING. WINDS WILL REMAIN BREEZY IN THE EVENING WITH GUST
UP TO 20 KTS POSSIBLE. WINDS WILL BEGIN TO DIMINISH AFTER
MIDNIGHT TO AROUND 5 TO 10 KTS. SATURDAY AFTERNOON WINDS WILL
SWITCH AGAIN TO THE SOUTHWEST AROUND 5 TO 15 KTS.
LBF WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...NMJ
LONG TERM...NMJ
AVIATION...GOMEZ
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page