Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 161806
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
106 PM CDT SAT AUG 16 2014

.SYNOPSIS...
ISSUED AT 345 AM CDT SAT AUG 16 2014

WEAK NORTHWESTERLY FLOW ALOFT CONTINUES ACROSS THE CENTRAL PLAINS
TONIGHT AS HIGH PRESSURE REMAINS ANCHORED ACROSS THE SWRN US.
CLOSED LOW PRESSURE WAS NOTED OVER EASTERN WASHINGTON STATE WITH A
SECOND CLOSED LOW OVER SRN QUEBEC. A WEAK UPPER LEVEL DISTURBANCE
WAS NOTED OVER EASTERN NEBRASKA...WITH A SECONDARY DISTURBANCE
OVER FAR SWRN NORTH DAKOTA. ACROSS WESTERN AND NORTH CENTRAL
NEBRASKA...SKIES WERE MOSTLY CLEAR WITH THE EXCEPTION OF THE FAR
NORTHEASTERN ZONES WHERE SOME PATCHY FOG AND HIGH LEVEL CLOUDS
WERE NOTED. AT THE SURFACE...A TROUGH OF LOW PRESSURE EXTENDED
FROM AROUND KONL SWD TO SOUTH CENTRAL KANSAS. PATCHY FOG HAS
DEVELOPED INVOF OF THIS FEATURE THIS MORNING AND WAS IMPACTING THE
EASTERN PORTION OF THE FORECAST AREA. FURTHER WEST...LIGHT
WESTERLY WINDS WERE PRESENT WITH MAINLY CLEAR SKIES. TEMPERATURES
AS OF 3 AM CDT...RANGED FROM 60 AT OGALLALA TO 68 AT ONEILL.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 345 AM CDT SAT AUG 16 2014

TODAY AND TONIGHT...THE MAIN FORECASTING CHALLENGE IS THE SMALL
THREAT FOR PCPN IN THE EASTERN CWA TODAY AND EARLY THIS EVENING.
FOR THE BULK OF THE FORECAST AREA...MOSTLY CLEAR SKIES AND LIGHT
WESTERLY AND NORTHWESTERLY WINDS WILL USHER IN SLIGHTLY DRIER AIR
TO LOCATIONS WEST OF HIGHWAY 83 TDY. EAST OF THIS ROUTE...INVOF OF
THE SURFACE TROUGH...LIGHT WINDS AND A MOIST BOUNDARY LAYER WILL
PREVAIL WITH DEW POINTS IN THE MID AND UPPER 60S TDY. LATER THIS
MORNING...WEAK MID LEVEL WARM AIR ADVECTION WILL SLIDE EAST ACROSS
THE EASTERN DAKOTAS AND NORTHERN NEBRASKA. WITH SURFACE HEATING
AND A VERY WEAK CAP...SHRAS AND TSRAS SHOULD DEVELOP INVOF THE
SURFACE TROUGH BY MIDDAY. DEEP LAYER WIND SHEAR REMAINS WEAK THIS
AFTERNOON AND EARLY THIS EVENING...SO ANY STORMS WHICH DO DEVELOP
WILL BE SUB SEVERE IN NATURE. MID LEVEL WAA WILL SHIFT EAST OF THE
FORECAST AREA BY EARLY EVENING...ENDING THE THUNDERSTORM THREAT BY
MID EVENING. WITH RESPECT TO TEMPERATURES TODAY...HIGHS WILL VARY
WIDELY ACROSS THE FORECAST AREA...RANGING FROM THE LOWER 80S IN
CLOUDY AREAS OF THE NORTHEAST...TO THE LOWER TO MIDDLE 90S IN THE
SOUTHWEST. LOWS TONIGHT WILL RANGE FROM THE MIDDLE 60S IN THE
EAST...TO THE UPPER 50S IN THE WEST.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 345 AM CDT SAT AUG 16 2014

12Z SUNDAY AND BEYOND. THE NAM...GFS AND ECMWF CONTINUE TO
INDICATE A CONVECTIVE SIGNAL SUNDAY AFTERNOON AND EVENING ACROSS
NORTHWEST TO NORTH CENTRAL NEBRASKA AS A DRYLINE BULGES EAST WITH
A SFC TROUGH/WEAK COLD FRONT AND A SHORTWAVE CROSSES THE NORTHERN
PLAINS. ISOLATED STRONG TO SEVERE STORMS ONCE AGAIN APPEAR
POSSIBLE AS THE MODELS INDICATE UPWARDS TO 2000 J/KG OF CAPE AND
INCREASING BULK SHEAR /450-SFC/ OF 30-40KTS DURING STORM
INITIATION. PWATS INCREASE IN EXCESS OF 1.50" ACROSS NORTHERN
NEBRASKA...HEAVY RAIN MAY BE POSSIBLE AS WELL. POPS WILL CONTINUE
TO THE SOUTHEAST OVERNIGHT INTO MONDAY AS BEST FOCUS SHIFTS WITH
THE DEPARTING WAVE. THERE REMAINS TIMING ISSUES WITH THE
MODELS...SO WILL LIMIT POPS AT 45 PERCENT OR LESS FOR NOW THROUGH
12Z MONDAY.

TEMPERATURES COOL SLIGHTLY MONDAY UNDER WEAK POST FRONTAL
CONDITIONS...HIGHS WILL RANGE FROM THE MID 80S ACROSS THE NORTHEAST
WHERE RAIN CHANCES MAY LINGER THROUGH 18Z...LOWER 90S ACROSS THE
SOUTHWEST LOOK PROBABLE.

A LONGWAVE TROUGH WILL DEEPEN ACROSS THE WESTERN STATES EARLY NEXT
WEEK FORCING AN UPPER RIDGE ACROSS THE CENTRAL PLAINS...WITH
BUILDING HEIGHTS AND SUBSIDENCE ANTICIPATED...PRECIPITATION CHANCES
SHOULD BE LIMITED TO RIDGE RIDING WAVES.  BOTH THE GFS AND EC
SIMULATE A WAVE IMPACTING THE CENTRAL PLAINS TUESDAY EVENING INTO
WEDNESDAY...ALLBLEND PROCEDURE GENERATED WIDESPREAD 40 PERCENT POPS
TO ACCOUNT FOR THIS WAVE...WHICH SEEMS PLAUSIBLE AT THIS TIME.

THE UPPER PATTERN BECOMES SOMEWHAT MUDDLED BEYOND WEDNESDAY...BUT
THE GENERAL IDEA IS THAT THE CENTRAL PLAINS WILL RETURN UNDER THE
INFLUENCE OF SOUTHWEST FLOW LATE WEEK.  ADDITIONAL IMPULSES OF
ENERGY WILL BRING FURTHER OPPORTUNITIES FOR QPF FOR THE CWA...BUT
CONFIDENCE IN TIMING AND LOCATION OF THESE IMPULSES IS LOW...THUS
WILL MAKE NO MAJOR CHANGES TO THE CR ALLBLEND PROCEDURE AT THIS TIME.

TEMPERATURES TO REMAIN FAIRLY CONSISTENT BEYOND THE EARLY WEEK
COOLDOWN...HIGHS IN THE MID 80S FOR THE NORTHEAST...MID 90S ACROSS
THE SOUTHWEST IS A GOOD BET FOR MOST DAYS.  LOWS WILL REMAIN IN THE
UPPER 50S TO MID 60S THROUGHOUT THE EXTENDED.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 104 PM CDT SAT AUG 16 2014

CLEAR TO MOSTLY CLEAR SKIES ACROSS THE AREA FOR THE AFTERNOON. A
FEW ISOLD SHOWERS MAY IMPACT NORTH CENTRAL NEB...AROUND KONL...BUT
SHOULD REMAIN WELL EAST OF KVTN AND KLBF. TONIGHT WILL CONTINUE TO
SEE MOSTLY CLEAR SKIES WITH PATCH TO AREAS OF FOG ACROSS THE
PLATTE RIVER VALLEY AND PORTIONS OF NORTH CENTRAL...FROM KBBW TO
KONL...FROM AROUND 10Z THROUGH AROUND 13Z. THE FOG IS LIKELY TO BE
SHALLOW HOWEVER LOCALLY REDUCED VSBY TO 1SM OR LESS. TOMORROW ANY
FOG THAT DEVELOPS WILL QUICKLY LIFT TO WIDESPREAD VFR CONDITIONS
WHICH WILL CONTINUE THROUGH 18Z.

&&

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

&&

$$

SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...JACOBS
AVIATION...MASEK




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