Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 310419 AAB
AFDLBF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1119 PM CDT THU OCT 30 2014

.SYNOPSIS...
ISSUED AT 324 PM CDT THU OCT 30 2014

H5 ANALYSIS FROM THIS MORNING HAD A HIGHLY AMPLIFIED
PATTERN ACROSS THE CONUS AND CANADA. A BROAD TROUGH OF LOW PRESSURE
EXTENDED FROM NUNAVUT...SOUTH TO THE FLORIDA PANHANDLE. FURTHER
WEST...RIDGING EXTENDED FROM SRN AZ INTO WESTERN PORTIONS OF THE NW
TERRITORIES OF CANADA. LOW PRESSURE WAS NOTED IN THE GULF OF ALASKA
WITH A TROUGH EXTENDING SWD INTO THE EASTERN PACIFIC OCEAN. ACROSS
THE CENTRAL CONUS...NWRLY FLOW WAS PRESENT ACROSS THE ROCKIES AND
HIGH PLAINS. HT FALLS WERE NOTED OVER THE UPPER MISSISSIPPI VALLEY
WITH HT RISES NOTED ACROSS MONTANA AND NRN WYOMING. THIS SHOULD LEAD
TO FURTHER AMPLIFICATION OF THE H5 PATTERN ACROSS THE CENTRAL CONUS
OVER THE NEXT 24 HOURS. AT THE SURFACE...LOW PRESSURE WAS NOTED NEAR
DES MOINES IOWA WITH A FRONT EXTENDING SOUTH INTO MO AND NWRN OK. A
SECOND COLD FRONT EXTENDED WEST NORTHWEST OF THE LOW INTO NERN
NEBRASKA...WESTERN SOUTH DAKOTA AND NERN MONTANA. VISIBLE SATELLITE
IMAGERY THIS AFTERNOON HAS A NICE SHIELD OF LOW CLOUDS ON THE
LEADING EDGE OF THIS ARCTIC AIRMASS. ATTM...THE LEADING EDGE OF THE
CLOUD COVER IS JUST NORTH OF BOYD COUNTY AS OF 3 PM CDT.
TEMPERATURES THIS AFTERNOON UNDER MOSTLY CLEAR SKIES...RANGED FROM
53 AT AINSWORTH TO 65 TO OGALLALA.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 324 PM CDT THU OCT 30 2014

HIGH PRESSURE WILL BUILD SOUTH INTO THE NORTHERN PLAINS AND UPPER
MIDWEST THIS EVENING ALLOWING FOR COOLER TEMPERATURES AND THE
POSSIBILITY OF LOW STRATUS BY DAWN. NUMERICAL GUIDANCE IS
CONSISTENT INDICATING TEENS AND 20S ACROSS THE REGION EARLY FRIDAY
MORNING. TRENDED THE TEMPERATURE FORECAST TOWARD THE SLIGHTLY
WARMER MAV GUIDANCE AS THE EXPECTED STRATUS SHOULD HELP KEEP
TEMPERATURES SLIGHTLY WARMER. THE HIGH PRESSURE WILL CONTINUE EAST
TOWARD THE MID-MISSOURI VALLEY ON FRIDAY ALLOWING FOR STRONG
SOUTHERLY RETURN FLOW ATOP THE EASTERN HIGH PLAINS. WITH A TIGHT
PRESSURE GRADIENT IN PLACE...SOUTHERLY WINDS WILL BE ON THE BREEZY
SIDE...WITH GUSTS IN EXCESS OF 30 MPH POSSIBLE OVER THE EASTERN
PANHANDLE AND ADJACENT WESTERN SANDHILLS THROUGH THE AFTERNOON.
FURTHER EAST THE PRESSURE GRADIENT IS SHOWN TO BE MORE RELAXED
WITH LIGHTER WIND ANTICIPATED. THE STRATUS IS SHOWN TO DISSIPATE
QUICKLY ALLOWING FOR RETURN OF FULL SUN...AND WITH THE STRONG
SOUTHERLY FLOW...HIGHS SHOULD WARM BACK INTO THE LOWER 50S ACROSS
OUR WEST. HOWEVER AS COOLER AIR IS RECYCLED FROM THE EAST AND
SOUTHEAST...OUR FAR EASTERN ZONES WILL STRUGGLE TO REACH INTO THE
40S.

THERE ARE CONCERNS OF FOG OVERNIGHT TONIGHT ACROSS PORTIONS OF
SOUTHWESTERN NEBRASKA AND NORTH THROUGH THE CENTRAL SANDHILLS AND
POSSIBLY INTO NORTH CENTRAL NEBRASKA.  ATTM...CONFIDENCE IS NOT
SUFFICIENT ENOUGH FOR ANY THING MORE THAN PATCHY FOG MENTION IN THE
FORECAST AS NAM/RAP BUFR SOUNDINGS REVEAL A SHORT PERIOD OF JUST
ENOUGH OF SATURATION AT THE SURFACE FOR FOG.  THIS SATURATED LAYER
IS SHOWN TO QUICKLY DRY.  IN ADDITION...THE 15Z SREF PROBS INDICATE
LESS THAN A 30% CHANCE OF SFC VISIBILITY AT OR BELOW 3SM...BUT
INDICATES 60-80% PROBS OF CEILINGS BELOW 1000FT.  ATTM...FAVORING
THE STRATUS RATHER THAN THE FOG...BUT FELT THAT A PATCHY MENTION WAS
WARRANTED.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 324 PM CDT THU OCT 30 2014

TEMPERATURES WILL BE THE
MAIN FORECAST CHALLENGE IN THE MID RANGE AS THE CENTRAL CONUS
TRANSITIONS FROM NWRLY FLOW ALOFT...TO RIDGING...TO SWRLY FLOW ALOFT
LATE SUNDAY. FOR FRIDAY NIGHT...HIGH PRESSURE WILL TRACK FROM THE
UPPER MISSISSIPPI VALLEY INTO THE MID MISSISSIPPI VALLEY BY 12Z
SATURDAY. DECENT SRLY WINDS WILL DEVELOP ON THE BACK SIDE OF THE
SURFACE HIGH OVERNIGHT FRIDAY NIGHT. TEMPERATURE GUIDANCE FOR NORTH
PLATTE FOR FRIDAY NIGHT WAS RIGHT AROUND 20 DEGREES WITH AROUND 25
FOR VALENTINE. WITH SRLY WIND EXPECTED AT 10 TO 15 MPH
OVERNIGHT...BOOSTED GUIDANCE MINS AROUND 5 DEGREES FOR THE FORECAST.
ON SATURDAY...SRLY WINDS WILL CONTINUE ACROSS THE EASTERN 2/3RDS OF
THE FORECAST AREA. COLD AIR WILL RECYCLE ON THE BACK SIDE OF EXITING
HIGH PRESSURE WITH HIGHS RANGING FROM THE UPPER 40S IN THE EAST...TO
THE 50S EAST OF HIGHWAY 61. ACROSS THE PANHANDLE COUNTIES...WARMER
H85 AIR WILL BEGIN TO PUSH EAST OF THE FRONT RANGES OF COLORADO AND
WYOMING...ALLOWING HIGHS TO REACH THE LOWER 60S IN THE PANHANDLE. ON
SATURDAY NIGHT...RIDGING ALOFT WILL BEGIN TO TRANSITION EAST INTO
THE MISSISSIPPI VALLEY...WITH A DEEPENING TROUGH ALOFT NOTED OVER
THE INTERMOUNTAIN WEST. THIS APPROACHING TROUGH ALOFT...WILL ALLOW A
SURFACE TROUGH TO DEVELOP ALONG THE FRONT RANGES OF COLORADO AND
WYOMING...LEADING TO SRLY WINDS OF 10 TO 15 MPH SATURDAY NIGHT. LIKE
FRIDAY NIGHT...WENT AHEAD AND FORECASTED ABOVE GUIDANCE TEMPS BASED
ON EXPECTED WINDS SATURDAY NIGHT. WHICH...WILL LEAD TO ABOVE NORMAL
LOWS IN THE LOWER TO MIDDLE 30S. ON SUNDAY...THE UPPER LEVEL TROUGH
ACROSS THE INTERMOUNTAIN WEST...WILL LIFT TO THE NORTH INTO MONTANA
AND WYOMING. EAST OF THIS FEATURE...WARM AIR WILL PUSH INTO THE
REMAINDER OF THE FORECAST AREA. BASED ON EXPECTED H85 TEMPS AND
DECENT MIXING HIGHS IN THE UPPER 60S TO LOWER 70S LOOK ON TRACK. IN
ADDITION TO WARM AIR...INCREASED LOW LEVEL MOISTURE WILL PUSH INTO
SOUTH CENTRAL AND EASTERN NEBRASKA SUNDAY AFTERNOON AND SUNDAY
NIGHT. BY SUNDAY NIGHT AS THE UPPER LEVEL TROUGH LIFTS INTO NORTH
DAKOTA...A SECONDARY DISTURBANCE WILL LIFT ACROSS THE CENTRAL AND
SRN PLAINS. THE DISTURBANCE WILL FORCE A COLD FRONT THROUGH THE
REGION SUNDAY NIGHT...LEADING TO AN INCREASED THREAT FOR RAIN
SHOWERS AS THE FRONT HITS INCREASED MOISTURE OVER SOUTH CENTRAL AND
EASTERN NEBRASKA. BASED ON THE LATEST NAM AND GFS SOLNS...AND THEIR
LOCATION OF THE BEST LOW LEVEL MOISTURE...MOST OF THE THREAT FOR
SHOWERS SUNDAY NIGHT WILL BE EAST OF THE FORECAST AREA. INHERITED
FCST HAD CHANCE POPS AOA 30 PERCENT SUNDAY NIGHT. DECIDED TO TAPER
THESE BACK INTO THE 15 TO 20 PERCENT RANGE GIVEN THE LACK OF
BOUNDARY LAYER MOISTURE ACROSS WESTERN AND NORTH CENTRAL NEBRASKA.
ANY PCPN WHICH DOES OCCUR WILL BE OF THE TOP DOWN SATURATION
VARIETY...AND WILL BE VERY LIGHT AT BEST.

LONG TERM...MONDAY THROUGH THURSDAY...ON MONDAY...THE UPPER LEVEL
TROUGH WILL TRACK ACROSS THE DAKOTAS WITH A SECONDARY SHORTWAVE
TRACKING ACROSS THE SOUTHERN PLAINS. MOISTURE IN ASSOCIATION WITH
THESE FEATURES WILL REMAIN LIMITED...SO NO REASON TO INTRODUCE POPS
T THIS TIME. THE TROUGH WILL MIGRATE EAST INTO THE MISSISSIPPI VALLEY
MONDAY NIGHT INTO TUESDAY WITH COOL AND TRANQUIL WEATHER EXPECTED.
HIGHS MONDAY AND TUESDAY WILL BE IN THE 50S. RIDGING ALOFT WILL
SLOWLY MIGRATE EAST INTO THE CENTRAL PLAINS WEDNESDAY INTO
THURSDAY....RESULTING CONTINUED DRY CONDITIONS AND IN HIGHS BACK IN
THE 60S.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1114 PM CDT THU OCT 30 2014

THE MVFR/IFR CIGS ACROSS SD/NERN NEB WILL DEVELOP WESTWARD
THROUGH THE NEB PANHANDLE OVERNIGHT AND THEN DISSIPATE 18Z-21Z
FRIDAY. THE SATELLITE DERIVED LCB PRODUCT INDICATES IFR CIGS ACROSS
SWRN SD THIS EVENING AND THESE CIGS SHOULD SPREAD INTO WRN NEB BY
MORNING.

CLEARING/VFR IS EXPECTED EAST OF HIGHWAY 83 09Z-12Z AS DEEPER MORE
STABLE HIGH PRESSURE BUILDS INTO THIS AREA. IMPROVEMENT TO VFR
OCCURS LATER FARTHER WEST ACROSS THE PANHANDLE...POSSIBLY AS LATE
AS 21Z FRIDAY.

NOTE...LOCAL LIFR CONDITIONS MAY DEVELOP ALONG THE WRN FRINGE OF
THE STRATUS DECK AND THIS IS MOST LIKELY ALONG AND WEST OF HIGHWAY
61 FRIDAY MORNING...09Z-15Z.

MVFR/IFR CIGS MAY REDEVELOP WEST OF HIGHWAY 61 FRIDAY
EVENING 04Z-06Z. VFR IS EXPECTED ELSEWHERE.

&&

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

$$

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






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