Area Forecast Discussion
Issued by NWS North Platte, NE

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KLBF 231126 AAA
AFDLBF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
626 AM CDT TUE SEP 23 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 353 AM CDT TUE SEP 23 2014

TODAY AND TONIGHT...THE UPPER LOW ACROSS WRN SD MOVES EAST TODAY AND
A PORTION OF THE COLD POOL AFFECTS NRN NEB TRIGGERING TSTMS THIS
AFTN AROUND VALENTINE. A CHECK ON THE NAM AND OTHER MODELS SEVERE
WEATHER PARAMETERS INDICATES LIMITED SEVERE WEATHER POTENTIAL. THE
BEST INSTABILITY IS ACROSS KS. ACROSS NRN NEB CAPE INCREASES TO
AROUND 1000 J/KG WITH MODEST EFFECTIVE BULK SHEAR IN THE RANGE OF 20
TO 30 KT. THUS STRONG TO ISOLATED SEVERE STORM POTENTIAL IS IN PLACE
BUT APPEARS TO BE LIMITED BY WEAK WIND FIELDS. POPS ARE SET TO
AROUND 40 PERCENT WITH LITTLE OR NO CHANCE FARTHER SOUTH NEAR NORTH
PLATTE. THIS CONVECTION IS EXPECTED TO WEAKEN AND MOVE SLOWLY EAST
THRU NCNTL NEB TONIGHT.

THE RAIN EARLY THIS MORNING ACROSS NCNTL NEB COULD LAST UNTIL 15Z AS
IT IS MOVING EAST AT ONLY 10 KT.

THE MODELS SHOW HEIGHTS BUILDING ACROSS WRN NEB THIS AFTN WHICH
SUPPORTS HIGHS IN THE 80S WITH SUNNY SKIES...70S ELSEWHERE. THE NAM
SHOWS DRY AIR MOVING IN ALOFT ACROSS NCNTL NEB TONIGHT AND THE
VISIBILITY PRODUCT INDICATES FOG...THE MET GUIDANCE DOES NOT. PATCHY
FOG MAY DEVELOP EAST OF HIGHWAY 83 AFTER MIDNIGHT TONIGHT.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 353 AM CDT TUE SEP 23 2014

FORECAST FOCUS FOR THIS PERIOD IS ON TEMPERATURES WEDNESDAY
THROUGH SATURDAY...THEN SWITCHES TO RAIN CHANCES FOR THE EARLY
PARTS OF NEXT WEEK.

MODELS ARE IN FAIR AGREEMENT THROUGH THURSDAY...THEN BEGIN TO
DIVERGE IN TERMS OF DETAILS OF THE UPPER LEVEL SYSTEM WHICH IS NOW
OVER THE NORTHERN PLAINS AS IT REGRESSES WESTWARD THROUGH THE
WEEKEND. MEANWHILE...GOOD AGREEMENT IS BEING SEEN WITH THE LARGE
SCALE FLOW THROUGH THE WEEKEND AS A STRONGLY AMPLIFIED TROUGH
MOVES ONTO THE WEST COAST...FURTHER AMPLIFYING THE RIDGE PLACED
OVER THE EASTERN TWO-THIRDS OF THE COUNTRY.

BEGINNING WEDNESDAY...THE UPPER LEVEL SYSTEM CURRENTLY OVER THE
NORTHERN AND CENTRAL PLAINS WILL HAVE MOVED EAST OF THE
AREA...ALLOWING SUBSIDENT FLOW TO IMPACT THE AREA. THIS WILL LEAD
TO GENERALLY SUNNY SKIES WHICH WILL HELP THE SURFACE TO WARM TO
ITS HIGHEST POTENTIAL. TEMPERATURES ALOFT WILL HAVE INCREASED...
SO MIXING OUT THE BOUNDARY LAYER PUTS HIGHS IN THE MID AND UPPER
80S...POTENTIALLY NEAR 90 FOR MOST LOCATIONS IN THE AFTERNOON. ONE
CAVEAT IS THAT THE NAM IS SHOWING THE POTENTIAL FOR FOG WEDNESDAY
NIGHT/THURSDAY MORNING OVER NORTH CENTRAL NEBRASKA. THE GFS ALSO
HAS THE SIGNAL FOR GOOD MOISTURE TRAPPED IN THE BOUNDARY
LAYER...BUT PUTS IT FURTHER EAST AND ONLY THE PERIPHERY LIES ON
THE EASTERN BORDERS OF THE LOCAL FORECAST AREA.

ON THURSDAY AS THE UPPER LEVEL SYSTEM MOVES EAST...IT GETS CAUGHT
UNDER THE RIDGE AND BEGINS TO RETROGRADE BACK TO THE SOUTHWEST.
AGAIN...MODELS HAVE SOME DIFFERENT OPINIONS ON HOW THIS WILL PLAY
OUT...BUT FOR THE MOST PART BRING THE WEAKENED CIRCULATION BACK
DOWN INTO NEBRASKA AND KANSAS. FLOW IN THE LOWER LEVELS WILL STAY
FROM THE SOUTH WHICH WILL KEEP DEWPOINTS FAIRLY HIGH FOR THIS TIME
OF YEAR...IN THE 50S AND LOW 60S IN PLACES. DESPITE THE MORE MOIST
AIR IN THE LOW LEVELS...DRY AIR WILL BE ABUNDANT ALOFT SO EVEN
WITH SOME INCREASED UPWARD MOTION AS THE UPPER LEVEL LOW MOVES
CLOSER TO THE AREA...DON/T EXPECT TO GET RAIN THROUGH SATURDAY.
THURSDAY CURRENTLY LOOKS TO BE THE WARMEST DAY OF THE WEEK...AS
AGAIN DRY AIR WILL HELP LEAD TO DEEP MIXING OF THE BOUNDARY LAYER
AND THEREFORE STRONG WARMING. THE WARMER AIR ALOFT WILL BE IN
PLACE ACROSS THE WESTERN HALF OF THE FORECAST AREA INTO THE
ROCKIES AND UP INTO THE NORTHERN PLAINS. THIS WILL OCCUR AS THE
THERMAL RIDGE BUILDS TO THE NORTHEAST OVER THE UPPER LOW SITTING
OVER THE LOCAL AREA. HIGHS THURSDAY ARE EXPECTED IN THE MID AND
UPPER 80S...WITH SOME PLACE REACHING THE LOW 90S.

AS MENTIONED ABOVE...A DEEP TROUGH WILL MOVE ONSHORE OVER THE WEST
COAST EARLY THIS WEEKEND. MODELS ARE IN DECENT AGREEMENT WITH A
LOW CLOSING OFF AS THE LONG-WAVE TROUGH MOVES ONSHORE BEFORE
WEAKENING AS THE WHOLE SYSTEM STARTS MOVING EAST THROUGH THE FIRST
PART OF NEXT WEEK. THE MAIN DIFFERENCES BETWEEN THE MODELS WILL BE
HOW FAST THE SYSTEM MOVES EAST INTO NEXT WEEK. DUE TO THE STRENGTH
OF THE UPPER LEVEL RIDGE...BELIEVE A SLOWER PROGRESSION WILL BE
THE WAY TO GO AS IT WILL CAUSE THE CLOSED SYSTEM TO STRUGGLE TO
MOVE INTO THE AREA UNDER THE RIDGE/S INFLUENCE. AGAIN...THIS WOULD
ALSO INDICATE A WEAKENING TREND OF THE SYSTEM. THE TREND IN THE
FORECAST HAS BEEN TO SLOW THE PROGRESSION OF THIS SYSTEM...AND
THEREFORE SLOW THE INTRODUCTION OF ASSOCIATED RAIN CHANCES. STILL
CONTINUE TO HAVE CHANCES FOR SHOWERS AND THUNDERSTORMS ON SUNDAY
OVER THE EASTERN PANHANDLE...BUT MAY HAVE TO BACK OFF FURTHER AS
THE SLOWER SOLUTIONS WOULD SUGGEST THE NEED TO HOLD OFF ON ANY
MENTION OF RAIN UNTIL MONDAY. WITH THE UPPER LEVEL TROUGH PUSHING
THE RIDGE EASTWARD...EXPECTING COOLER CONDITIONS THROUGH THE
WEEKEND...WITH TEMPERATURES CLOSER TO NORMAL VALUES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 626 AM CDT TUE SEP 23 2014

AN AREA OF IFR/MVFR CIGS HAS DEVELOPED ACROSS NCNTL/SCNTL NEB. THE
RAP MODEL SUGGESTS THESE CIGS WOULD IMPROVE TO VFR BY 15Z-17Z.
THEREAFTER...THE UPPER LOW ACROSS WRN SD SHOULD MOVE INTO SCNTL SD
AND SPAWN SCATTERED SHRA/ISOLD TSTMS ACROSS NRN NEB WHICH WOULD
MOVE EAST DURING THE EVENING AND EXIT THE FCST AREA 06Z-12Z WEDS.

THE NAM SHOWS DRY AIR ALOFT MOVING INTO NCNTL NEB WITH FOG
DEVELOPING 06Z-12Z WEDS EAST OF HIGHWAY 83 THROUGH KONL.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...CDC
LONG TERM...BROOKS
AVIATION...CDC






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.