Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 240039 AAA
AFDLBF

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

.SYNOPSIS...
ISSUED AT 335 PM CDT TUE SEP 23 2014

UPPER LEVEL LOW SPINNING NEAR THE NEB/S DAKOTA BORDER THIS
AFTERNOON. AN UPPER LEVEL DISTURBANCE IS PUSHING EAST WITH STILL
SOME LINGER STRATUS ACROSS EASTERN NEBRASKA. MEANWHILE A SFC
TROUGH/WIND SHIFT IS PUSHING ACROSS WESTERN NEBRASKA. WINDS
SOUTHERLY AHEAD OF THE TROUGH...WITH WESTERLY WINDS BEHIND. MOSTLY
SUNNY SKIES ACROSS MUCH OF THE REGION HAS ALLOWED TEMPS TO WARM INTO
THE MID 70S TO MID 80S...WARMEST ACROSS THE SW. FAR EASTERN CWA
STILL IN THE 60S DUE TO THE LOW CLOUDS. A FEW RAIN
SHOWERS...WRAPPING AROUND THE UPPER LOW ACROSS NW NEB...INTO N
CENTRAL.

&&

.UPDATE...
ISSUED AT 738 PM CDT TUE SEP 23 2014

FORECAST HAS BEEN UPDATED FOR PRECIPITATION CHANCES DUE TO THE
TRENDS IN THE ONGOING SHOWERS AND STORMS. SCATTERED TO BROKEN
SHOWERS AND STORMS WERE BEING OBSERVED WITH THE BACK LINE ROUGHLY
FROM NORTHEAST LINCOLN COUNTY UP THROUGH HOLT COUNTY. THE
STRONGEST STORMS WERE OBSERVED ACROSS CUSTER COUNTY AT THE PRESENT
TIME WITH SHOWERS AND WEAK ISOLATED TO SCATTERED THUNDERSTORMS
ELSEWHERE. THIS ACTIVITY WILL CONTINUE TO MOVE SOUTH AND EAST
THROUGH THE COMING HOURS AND THE FORECAST HAS BEEN TRENDED THAT
DIRECTION ACCORDINGLY. WITH LOSS OF SUN...SURFACE BASED
INSTABILITY WILL BE ON THE DECREASE...HOWEVER MODELS ARE SHOWING
AN INCREASE IN THE LOW LEVEL JET IN THE NEXT SEVERAL HOURS WHICH
MAY CONTINUE TO BRING LIFT TO THE REGION AND CONTINUE THE ACTIVITY
INTO THE LATE EVENING HOURS. THE LOW LEVEL JET WILL QUICKLY VEER
EASTWARD SO BELIEVE ALL SHOWERS AND STORMS SHOULD BE OUT OF THE
LOCAL AREA SHORTLY AFTER MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 335 PM CDT TUE SEP 23 2014

UPPER LEVEL LOW WILL CONTINUE TO PUSH EAST OVERNIGHT. INSTABILITY IS
INCREASING THIS AFTERNOON ALONG/AHEAD OF THE TROUGH LINE. NEAR TERM
MODELS ARE SHOWING A WEAKENING CAP WITH A BROKEN LINE OF STORMS TO
FIRE OVER THE NEXT FEW HOURS. THE RUC IS MORE ROBUST THAN THE OTHER
MODELS...ALTHOUGH BOTH THE HRRR OR THE NAM DO DEVELOP A LINE. SHEAR
IS MARGINAL...30 KTS OR LESS...AND NARROW BAND OF LESS THAN A 1000
J/KG OF CAPE SO WIDESPREAD SEVERE WEATHER IS NOT EXPECTED. CANNOT
RULE OUT A STRONG STORM OR TWO...ESPECIALLY FROM HAIL AS FREEZING
LEVELS IS CLOSE TO 13000 FT ASL.

THE ACTIVITY WILL QUICKLY PUSH EAST WITH ANY STORMS PUSHING EAST OF
THE CWA BY MORNING. MEANWHILE SOME DRY AIR TO FILL IN BEHIND THE
TROUGH. MODELS SUGGESTING A DRY LAYER TO TRAP SOME LOW LEVEL
MOISTURE ACROSS N CENTRAL TOWARDS MORNING WHICH COULD RESULT IN SOME
FOG...AND CONTINUED TO MENTION PATCHY FOG AFTER SHOWERS END.

TOMORROW DRY AIR CONTINUES TO SPREAD ACROSS THE CWA WITH CLEARING
SKIES AND A NICE WARM UP ACROSS THE BOARD AS RIDGE BUILDS ACROSS THE
CENTRAL ROCKIES. MOST AREAS SHOULD PUSH INTO THE 80S...WITH THE FAR
WESTERN ZONES NEARING 90.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 335 PM CDT TUE SEP 23 2014

WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...

THIS PERIOD WILL BE HIGHLIGHTED BY AN AMPLIFIED UPPER TROUGH
MOVING ONTO THE WEST COAST AND A POSITIVELY TILTED UPPER RIDGE
EXTENDING ACROSS THE CENTRAL ROCKIES INTO THE CENTRAL AND NORTHERN
PLAINS. SUNNY SKIES AND HIGHS THURSDAY AND FRIDAY IN THE MID TO
UPPER 80S. THESE HIGHS TO BE AT LEAST 10 TO 15 DEGREES ABOVE
NORMAL. SOUTHERLY WINDS 10 TO 15 MPH THURSDAY TO INCREASE TO 15 TO
25 MPH BY FRIDAY AFTERNOON. MILD EACH NIGHT WITH LOWS ALSO 10 TO
15 DEGREES ABOVE NORMAL RANGING FROM 55 TO 60.

SATURDAY THROUGH TUESDAY...

THE UPPER TROUGH/CLOSED LOW ALONG THE WEST COAST ON SATURDAY WILL
LIFT NORTHEAST INTO WYOMING AND MONTANA BY MONDAY. THE 12Z ECMWF
IS ABOUT 12-18 HRS FASTER WITH THE UPPER TROUGH THAN THE 12Z GFS.
WITH THE 12Z GEM IN CLOSE AGREEMENT WITH THE ECMWF...PREFERENCE
LIES WITH THE ECMWF. LATEST SUPERBLEND POPS FOR A SLIGHT CHANCE
SUNDAY NIGHT WITH NEAR 30 POPS MONDAY INTO MONDAY NIGHT LOOK ON
TRACK. BY TUESDAY...H5 HEIGHT DIFFERENCE ARE NEAR 120 METERS
ACROSS IDAHO AND UTAH. THIS IS DUE TO THE GFS WITH ZONAL FLOW
ACROSS THE REGION AND THE ECMWF FORECASTING AN UPPER TROUGH.

TEMPERATURES WILL REMAIN ABOVE NORMAL IN THE LOWER 80S SATURDAY
AND UPPER 70S SUNDAY...COOLING TO NEAR NORMAL IN THE MID 70S
MONDAY AND TUESDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 634 PM CDT TUE SEP 23 2014

BOUNDARY EVIDENT ON KLNX RADAR DRIFTING SWD SLOWLY AND STRONG TO
SEVERE TSRA HAVE DEVELOPED ALONG A SMALL PORTION OF THE BOUNDARY
ACROSS CUSTER CO. TCU TO SMALL CB DEVELOPING ALONG BOUNDARY JUST
NORTH OF KLBF BUT AGGRESSIVE DEVELOPMENT NOT EMINENT BASED ON
VISUAL INSPECTION SO HAVE INCLUDED ONLY VCTS FOR KLBF THROUGH 02Z
WHEN LOSS OF DAYTIME HEATING SHOULD REDUCE REALIZED INSTABILITY.
HOWEVER...LLJ DEVELOPMENT AND ASSOCIATED MID LEVEL INSTABILITY LATER
MAY SUSTAIN TSRA FURTHER NORTH AND EAST OF KLBF. NAM/GEM AND TO
SOME DEGREE THE HIRES NMM DID A DECENT JOB CAPTURING TEMPORAL AND
SPATIAL DETAILS OF CONVECTION...AND MOVE THE PRECIP EAST OF THE
CWA BY MIDNIGHT. THEREFORE HAVE NOT INCLUDED TSRA FOR KVTN THIS
EVENING.

BEYOND THIS...MID LEVEL CONVECTIVE DEBRIS SHOULD CLEAR BY LATE
EVENING AND MAINLY SKC AFTER THAT. WINDS WILL BE MAINLY LIGHT
THROUGH THE DAY TMRW.


&&

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

$$

UPDATE...BROOKS
SYNOPSIS...MASEK
SHORT TERM...MASEK
LONG TERM...ROBERG
AVIATION...JWS








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