Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 292048
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
348 PM CDT SAT AUG 29 2015

.SYNOPSIS...
ISSUED AT 348 PM CDT SAT AUG 29 2015

A STRONG TROUGH OF LOW PRESSURE ALOFT WAS PRESENT FROM
THE ALASKAN PANHANDLE...SWD TO OFF THE COAST OF NRN CA THIS MORNING.
DECENT HT FALLS OF 50 TO 100 METERS WERE NOTED FROM NRN CA INTO SWRN
BRITISH COLUMBIA. JUST EAST OF THE TROUGH AXIS...A NICE 70 TO 90 KT
H5 JET EXTENDED FROM NRN CA INTO SRN BRITISH COLUMBIA. DOWNSTREAM OF
THIS TROUGH...HIGH PRESSURE WAS LOCATED OVER THE FOUR CORNERS WITH A
RIDGE EXTENDING INTO EASTERN PORTIONS OF THE NW TERRITORIES OF
CANADA. ACROSS THE EASTERN CONUS...A SHORTWAVE TROUGH EXTENDED FROM
LAKE SUPERIOR INTO NRN ILLINOIS...WHILE A CLOSED LOW WAS NOTED JUST
SOUTH OF THE FL PANHANDLE. AT THE SURFACE...WEAK HIGH PRESSURE WAS
PRESENT ACROSS NEBRASKA...WHILE A SURFACE TROUGH OF LOW PRESSURE WAS
PRESENT FROM EASTERN MONTANA SOUTH TO EASTERN COLORADO. WINDS WERE
GENERALLY LIGHT THIS AFTERNOON AND SKIES WERE MOSTLY
CLEAR...HOWEVER...A VEIL OF HAZE AND SMOKE ALOFT WAS PRESENT ACROSS
THE FORECAST AREA. TEMPERATURES AS OF THE 3 PM CDT HOUR...RANGED
FROM 85 AT ONEILL TO 92 AT OGALLALA AND IMPERIAL.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 348 PM CDT SAT AUG 29 2015

CONCERN IS MAINLY TEMPS AND FOG. SMOKE FROM WESTERN FIRES CAUSING
HAZY SKIES...HOWEVER THIS SEEMS TO ONLY HAVE MINOR IMPACT ON TEMPS.
THUS OVERNIGHT HAVE BLENDED GUIDANCE TO SIDED ON THE WARM SIDE WHICH
DROPS TEMPS INTO THE LOWER 60S TO MID 50S. THERE IS A NOCTURNAL LL
JET THAT DEVELOPS OVER THE WESTERN ZONES AND NOSES INTO S CENTRAL S
DAKOTA. EXPECT THE JET TO KEEP LOWS THERE THE MILDEST. AS FOR THE
FOG...LIMITED MIXING TODAY IN THE VALLEY AND OVER PORTIONS OF N
CENTRAL...WHERE FOG BRIEFLY DEVELOPED THIS MORNING. HAVE DECIDED TO
GO CLOSE TO PERSISTENCE...EVEN THOUGH THE SHREF PLUMS SUGGEST
DEVELOPMENT SHOULD BE FURTHER EAST. PART OF THE REASONING WAS THE
SHREF PLUMS YESTERDAY WERE NOT FAR ENOUGH WEST FOR WHAT RESULTED
THIS MORNING. THIS WILL NEED TO BE WATCHED CLOSELY.

TOMORROW THE RIDGE WILL CONTINUE TO DOMINATE THE AREA...WITH THE
THERMAL RIDGE TO BE ACROSS NW NEB. THIS AREA SHOULD BE THE
WARMEST...HIGHS IN THE MID TO UPPER 90S...WITH LOWER 90S ELSEWHERE.
SOME MOS GUIDANCE TAKES THE NW TO TRIPLE DIGITS...HOWEVER THE HAZE
WILL LIKELY REMAIN AND PREVENT THEM FROM TORCHING OUT. ANOTHER
CONCERN WILL BE THE FIRE DANGER ACROSS THE WEST. DRY LINE PUSHES DEW
PTS INTO THE 40S AND WILL COMBINE WITH THE MID TO UPPER 90S TO
PRODUCE MIN RH VALUES FROM 15 TO 20 PERCENT. WINDS ALSO GUSTING TO
AROUND 20 MPH. WHILE NOT CRITICAL CONDITIONS...A HIGH FIRE DANGER
CAN BE EXPECTED.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 348 PM CDT SAT AUG 29 2015

IN THE MID RANGE...A FROPA...AND
LIMITED PCPN CHANCES WILL BE THE MAIN FORECASTING CONCERNS. ON
SUNDAY NIGHT...AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL LIFT FROM
THE IDAHO PANHANDLE...INTO FAR NWRN ND BY 12Z MONDAY. THIS FEATURE
WILL FORCE A COLD FRONT INTO THE FAR NORTHWESTERN CWA BY DAYBREAK
MONDAY MORNING. LIFT IN THE VICINITY OF THE FRONT IS FARILY
IMPRESSIVE ATTM...HOWEVER BOTH THE NAM AND GFS SOLNS ARE INDICATIVE
OF VERY MEAGER LOW LEVEL MOISTURE IN THE NORTHWESTERN CWA...SO ANY
CONVECTION WHICH MAY DEVELOPS...WILL BE PRETTY ELEVATED. WITH THIS
IN MIND...WILL LIMIT POPS TO SLIGHT CHANCES ATTM. ALSO...WITH THE
FRONTAL TIMING SLIGHTLY SLOWER NOW...HAVE CONFINED POPS TO THE FAR
NORTHWESTERN CWA AND TAKEN THEM OUT OF THE SOUTHEASTERN PANHANDLE
AND PORTIONS OF NORTH CENTRAL NEBRASKA. THE UPPER LEVEL TROUGH WILL
LIFT INTO NORTHWESTERN ONTARIO ON MONDAY. THIS WILL FORCE THE COLD
FRONT THROUGH MOST OF THE FORECAST AREA...STALLING THIS ACROSS SWRN
TO NERN NEBRASKA BY MONDAY EVENING. AS THE FRONT PROGRESSES ON
MONDAY...FELT MOISTURE...AND MID LEVEL INSTABILITY WAS LACKING
CONSIDERABLY INVOF THE FRONT MONDAY...AND DECIDED TO LEAVE THE
FORECAST DRY FOR NOW. HIGHS MONDAY WILL RUN 5 TO 10 DEGREES COOLER
THAN SUNDAYS...AS THE FRONT WILL BE THROUGH MOST OF THE FA BY PEAK
HEATING. HIGHS WILL RANGE FROM THE MID 80S IN NRN NEBRASKA...TO THE
LOWER 90S IN THE FAR SOUTHWEST. AS MENTIONED EARLIER...THE FRONT
WILL STALL ACROSS SWRN...CENTRAL AND NERN NEBRASKA MONDAY EVENING.
AT THE SAME TIME...A DECENT MID LEVEL SHORTWAVE WILL TRACK FROM
EASTERN COLORADO INTO SRN NEBRASKA AND NRN KS...INITIATING
THUNDERSTORMS DURING THE EVENING HOURS. SB CAPES ALONG AND SOUTH OF
THE COLD FRONT...WILL REACH 2000 TO 3000 J/KG ALONG A NARROW
CORRIDOR IN THE EASTERN AND SERN PORTIONS OF THE CWA MONDAY EVENING
WHICH WOULD SUPPORT A STRONG STORM OR TWO. HOWEVER...BULK SHEAR IS
ONLY ON THE ORDER OF 20 TO 30 KTS MONDAY EVENING...SO SEVERE STORMS
ARE NOT ANTICIPATED ATTM. INHERITED FCST HAD A STRIP OF 20 POPS
ALONG THE FRONT AND THEY WILL BE CONTINUED. FOR TUESDAY...THE FRONT
WILL BEGIN TO WASH OUT ACROSS CENTRAL NEBRASKA TUESDAY AFTERNOON AS
WINDS TAKE ON A MORE SOUTHEASTERLY COMPONENT. THIS WILL FORCE LOW
LEVEL MOISTURE WEST INTO CENTRAL PORTIONS OF THE FORECAST AREA TUES
AFTN. THE COMBINATION OF THIS LOW LEVEL MOISTURE ALONG WITH
FAVORABLE MID LEVEL LIFT...WILL BRING PCPN CHANCES BACK INTO THE
FORECAST FOR SOUTHWESTERN...CENTRAL AND PORTIONS OF NORTH CENTRAL
NEBRASKA LATE TUES.

TUESDAY NIGHT THROUGH SATURDAY...THE MID RANGE MODEL SOLUTIONS
INCLUDING THE 12Z GFS AND 12Z ECMWF SOLNS...TREND TOWARD BUILDING AN
UPPER LEVEL RIDGE ACROSS THE CENTRAL AND EASTERN US...WITH A TROUGH
NOTED ALONG THE WESTERN QUARTER OF THE CONUS. THROUGH THE END OF THE
WEEK...THE HIGH PLAINS WILL REMAIN IN SWRLY FLOW ALOFT...USUALLY
CONDUCIVE TO PRECIPITATION. HOWEVER...DEW POINTS ARE GENERALLY IN
THE LOWER 50S NEXT WEEK...AND WITHOUT A DECENT LOW LEVEL BOUNDARY OR
FOCUSING MECHANISM FOR PCPN...WENT WITH A DRY FCST. I DID HOWEVER
BEGIN TO INCREASE PCPN CHANCES LATE NEXT WEEK AS THE UPPER LEVEL
TROUGH BEGINS TO MIGRATE EAST. AS THE UPPER LEVEL TROUGH MOVES
EAST...SRLY WINDS WILL INCREASE...LEADING TO INCREASED LOW LEVEL
MOISTURE ACROSS THE CENTRAL PLAINS. MID LEVEL INSTABILITY WILL
INCREASE AS WELL AS H5 TEMPS BEGIN TO COOL FRIDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 103 PM CDT SAT AUG 29 2015

VFR WITH SOME HIGH HAZE/CIRRUS DRIFTING ACROSS THE AREA THIS
AFTERNOON. OVERNIGHT SKIES CLEAR...ALTHOUGH COULD STILL SEE SOME
HIGH HAZE/SMOKE ACROSS THE AREA FROM THE PACIFIC NW FIRES.
BOUNDARY LAYER MOISTURE REMAINS HIGH AND EXPECT A REDEVELOPMENT
OF FOG/LOW STRATUS ACROSS PORTIONS OF SW INTO N CENTRAL NEBRASKA.
INCLUDED AT KLBF...HOWEVER EXPECT FOG TO BE SE OF THE KVTN
TERMINAL. TOMORROW A RETURN TO VFR IN THE MORNING.


&&

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

$$

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



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