772
FXUS63 KLBF 202056
AFDLBF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
356 PM CDT SUN OCT 20 2024
KEY MESSAGES
- SCATTERED THUNDERSTORMS ARE POSSIBLE (30-50%) AHEAD OF A
FRONTAL BOUNDARY NEAR AND EAST OF HWY 83 MONDAY AFTERNOON. A
FEW STORMS COULD BE STRONG TO SEVERE WITH A THREAT FOR HAIL.
- A SLIGHT CHANCE (15-20%) FOR RAIN SHOWERS EXISTS TUESDAY
NIGHT INTO WEDNESDAY MORNING NEAR HWY 20, THOUGH LITTLE TO NO
ACCUMULATION IS EXPECTED.
- INCREASING TEMPERATURES MIDDLE TO LATE WEEK WILL LEAD TO A
RETURN OF ELEVATED FIRE WEATHER CONCERNS.
SHORT TERM /THROUGH MONDAY NIGHT/
ISSUED AT 354 PM CDT SUN OCT 20 2024
CURRENTLY, GUSTY SOUTH WINDS PERSIST ACROSS ALL OF WESTERN AND NORTH
CENTRAL NEBRASKA, AS THE SURFACE PRESSURE GRADIENT REMAINS
CONSTRICTED ACROSS THE AREA. THIS IS A CONSEQUENCE OF THE AREA
REMAINING POSITIONED BETWEEN SURFACE HIGH PRESSURE OVER THE MIDSOUTH
AND BROAD SURFACE LOW PRESSURE ACROSS THE LEE OF THE ROCKIES. THE
BROAD SOUTHERLY FLOW HAS LED TO INCREASING MOISTURE RETURN ACROSS
THE AREA THIS AFTERNOON, WITH DEWPOINTS CLIMBING INTO THE LOW/MIDDLE
50S.
FOR TONIGHT AND TOMORROW, PERSISTENT WARM ADVECTION WILL KEEP LOWS
MILD IN THE 50S. AN INCREASING SOUTHERLY LLJ WILL PROMOTE SCATTERED
SHOWER AND THUNDERSTORM DEVELOPMENT EARLY MONDAY MORNING ACROSS
NORTHWEST KANSAS/EASTERN COLORADO, WHICH THEN LIFTS NORTHEAST INTO
SOUTHWEST NEBRASKA NEAR SUNRISE. THIS ROUND OF PRECIPITATION WILL
HAVE IMPLICATIONS ON FURTHER THUNDERSTORM DEVELOPMENT LATER IN THE
DAY, AND LENDS SOME UNCERTAINTY IN ANY SEVERE WEATHER POTENTIAL.
ALOFT, A CUTOFF LOW, CURRENTLY LOCATED OVER THE FOUR CORNERS REGION,
SHOULD SLOWLY LIFT NORTHWARD TONIGHT AND EJECT EASTWARD INTO THE
PLAINS TOMORROW MORNING. AS THIS LOW EJECTS INTO THE PLAINS, IT WILL
TAKE ON A NEGATIVE TILT AS IT SLOWLY BEGINS TO OCCLUDE. VERY COLD
TEMPERATURES ALOFT IN ASSOCIATION WITH THIS WAVE (-18 TO -20C AT H5)
WILL LEAD TO VERY STEEP LAPSE RATES AND INCREASING INSTABILITY
TOMORROW AFTERNOON. THE CURRENT THINKING IS A PERIOD OF CLEARING
SHOULD OCCUR, AS THE DRY SLOT BEGINS TO MOVE OVERHEAD BY EARLY
AFTERNOON. THIS WILL ALLOW FOR INCREASED SURFACE BASED INSTABILITY
ACROSS SOUTHWEST NEBRASKA, WHERE A NARROW MOISTURE AXIS (WITH
MID/UPPER 50 DEWPOINTS) WILL BE POSITIONED AHEAD OF BROAD SURFACE
LOW PRESSURE. EVEN IF TEMPERATURES WERE TO REMAIN IN THE LOW/MIDDLE
60S, THE VERY COLD AIR ALOFT WILL LEAD TO ROBUST LOW LEVEL
INSTABILITY. SCATTERED THUNDERSTORM INITIATION LOOKS TO OCCUR
DURING THE EARLY AFTERNOON BOTH AHEAD OF A DIFFUSE TRIPLE POINT
IN NORTH CENTRAL KANSAS/FAR SOUTHERN NEBRASKA AND AN
ENCROACHING PACIFIC FRONT ACROSS WESTERN NEBRASKA.
AS FOR THE ENVIRONMENT, GUIDANCE PAINTS 0-3CAPE VALUES
EXCEEDING 100J/KG (WITH POCKETS APPROACHING 200J/KG)
OVERSPREADING AREAS NEAR/EAST OF HWY 83 AND SOUTH OF HWY 2. WITH
THIS IN MIND, ANY SURFACE BASED THUNDERSTORMS WOULD PRESENT A
THREAT FOR LOW LEVEL ROTATION, AMID AMPLE POTENTIAL FOR LOW-
LEVEL VORTICITY STRETCHING. LOW LEVEL SHEAR REMAINS SOMEWHAT
MEAGER, LARGELY DUE TO THE LACK OF A MORE ROBUST SURFACE LOW TO
LOCALLY BACK SURFACE FLOW. STILL, WOULD NOT BE SURPRISED TO HAVE
FUNNEL CLOUDS, AND POSSIBLY A BRIEF TORNADO OR TWO GENERALLY
EAST OF HWY 83/SOUTH OF HWY 92, DEPENDING ON HOW FAVORABLY
SURFACE HEATING CAN OCCUR. THE OTHER THREAT WITH STORMS WOULD
LIKELY BE HAIL, THOUGH SOME UNCERTAINTY LINGERS DUE TO THE
DEGREE OF LOW-LEVEL INSTABILITY (UNFAVORABLE PARCEL ACCELERATION
THROUGH THE HAIL GROWTH ZONE) AND RATHER MESSY HODOGRAPHS.
STILL, A THREAT FOR LOW TOPPED SUPERCELLS ABOVE LOW FREEZING
LEVELS COULD LEAD TO A FEW INSTANCES OF SEVERE HAIL, PRIMARILY
NEAR AND EAST OF HWY 83. STORMS QUICKLY EXIT THE AREA AROUND
SUNSET, WITH DRY CONDITIONS PERSISTING THROUGH THE NIGHT. COLD
ADVECTION BEHIND THE AFOREMENTIONED FRONTAL BOUNDARY ALLOWS FOR
LOWS FALLING INTO THE 40S.
LONG TERM /TUESDAY THROUGH SUNDAY/
ISSUED AT 354 PM CDT SUN OCT 20 2024
A BRIEF LULL IN ACTIVITY IS EXPECTED DURING THE DAY TUESDAY, AS
SHORTWAVE RIDING QUICKLY TRANSLATES ACROSS THE AREA BEHIND THE
DEPARTING UPPER LOW. BY TUESDAY NIGHT, A QUICK MOVING SHORTWAVE WILL
DROP SOUTHWARD INTO THE NORTHERN PLAINS, WITH AN ASSOCIATED SURFACE
LOW MOVING EAST ACROSS THE INTERNATIONAL BORDER. THIS WILL DRAG A
COLD FRONT THROUGH THE AREA LATE TUESDAY AFTERNOON, WITH GUSTY NORTH
WINDS IN ITS WAKE. BY TUESDAY NIGHT A FEW SHOWERS ARE POSSIBLE (10-
30%) AS WARM ADVECTION BEGINS IN EARNEST, THOUGH CONFIDENCE
CONTINUES TO WANE IN ANY PRECIPITATION NEAR THE HWY 20 CORRIDOR.
LITTLE TO NO ACCUMULATION IS ANTICIPATED WITH ANY ACTIVITY.
AS WE HEAD TOWARD THE MIDDLE AND LATER PARTS OF THIS WEEK, UPPER
RIDGING WILL BEGIN TO AMPLIFY ACROSS THE WESTERN CONUS, AND THIS
LEADS TO TEMPERATURES MODERATING BACK TO ABOVE AVERAGE ACROSS THE
AREA. THIS, COMBINED WITH INCREASING DRY AIR, WILL LEAD TO A RETURN
OF FIRE CONCERNS AGAIN. WILL HAVE TO MONITOR THE STRENGTH OF WINDS
EACH DAY LATE WEEK, THOUGH AT LEAST A PERIOD OF ELEVATED TO NEAR-
CRITICAL FIRE CONCERNS IS EXPECTED TO DEVELOP ACROSS THE AREA YET
AGAIN.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1255 PM CDT SUN OCT 20 2024
VFR CONDITIONS ARE EXPECTED THROUGH THE FORECAST PERIOD.
MAIN AVIATION CONCERN WILL BE STRONG WINDS INITIALLY AT THE
SURFACE BUT TRANSLATING TO LLWS TONIGHT. PRECIPITATION WILL
ARRIVE FROM THE SOUTHWEST EARLY MONDAY MORNING. THIS WILL BE
PRECEDED BY INCREASING MID-LEVEL CLOUDINESS. FOR NOW, BELIEVE
ANY THREAT FOR RAIN AND/OR THUNDERSTORMS WILL BE CONFINED TO A
FEW HOURS AT LBF. CIGS AS WELL AS EXPECTED VISIBILITIES SHOULD
REMAIN IN VFR CRITERIA BUT THIS THREAT WILL BE MONITORED GOING
FORWARD. ADDITIONAL THUNDERSTORMS ARE PROBABLE JUST BEYOND THE
END OF THE VALID PERIOD.
LBF WATCHES/WARNINGS/ADVISORIES
NONE.
SHORT TERM...BROWN
LONG TERM...BROWN
AVIATION...NMJ
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