Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 290430
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
1130 PM CDT TUE OCT 28 2014

.SYNOPSIS...
ISSUED AT 233 PM CDT TUE OCT 28 2014

AT 1930Z...THE UPPER LEVEL PATTERN OVER THE CONUS IS PROGRESSIVE
WITH A LARGE TROUGH MOVING INTO THE EASTERN CONUS...AND A RIDGE
STEADILY AMPLIFYING OVER THE INTERMOUNTAIN WEST. NORTHWEST FLOW
ALOFT BETWEEN THESE TWO FEATURES...WITH DRY AIR AND CLEAR SKIES
ACROSS MOST OF THE CENTRAL PLAINS. AT THE SURFACE AND CLOSER TO THE
CWA...WINDS WERE NORTHWESTERLY AND BREEZY AT TIMES WITH GUSTS TO 25
OR 30 MPH. TEMPERATURES WERE NEAR OR JUST BELOW CLIMO RANGING FROM
THE LOW TO UPPER 50S.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 233 PM CDT TUE OCT 28 2014

CLEAR SKIES WILL CONTINUE THROUGH THE MAJORITY OF THE SHORT TERM
PERIOD AS LARGE SCALE SUBSIDENCE DOMINATES IN THE WAKE OF THE
DEPARTING TROUGH NOW IMPACTING THE GREAT LAKES REGION. CLEAR AND
CALM CONDITIONS TONIGHT WILL PROMOTE STRONG RADIATIONAL COOLING
OVERNIGHT. 12Z GUIDANCE HAS COME IN COOLER WITH LOWS TONIGHT...SO
THE INHERITED GRIDS HAVE BEEN NUDGED DOWN. H85 WINDS BECOME
SOUTHERLY OVERNIGHT AND USHER IN WARMER AIR...HOWEVER MOST OF THAT
WILL NOT BE REALIZED AT THE SFC WITH MINIMAL TO NO MIXING TAKING
PLACE. THE MIN T GRIDS MAY NEED TO BE TRENDED DOWN A FEW MORE
DEGREES IF GUIDANCE REMAINS ON THE COOL SIDE.

SOUTHERLY FLOW WILL BOOST TEMPERATURES BACK ABOVE CLIMO FOR
WEDNESDAY AFTERNOON. H85 TEMPS OF 10C TO 15C WILL MIX DOWN TO SFC
TEMPS IN THE 60S...WITH A FEW 70S POSSIBLE IN OUR FAR SOUTHWEST
ZONES. A 90+ KT UPPER LEVEL JET STREAK WILL BEGIN TO NOSE INTO THE
CWA LATE IN THE DAY AS A SHORTWAVE TROUGH MOVES INTO EASTERN MONTANA
AND THE DAKOTAS. THE ORIENTATION OF THE JET SHOULD KEEP THE MAIN SFC
LOW AND PRECIP CHANCES TO OUR NORTH AS THE CONVERGENT RIGHT EXIT
REGION OF THE JET STREAK MOVES OVER THE CWA.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 233 PM CDT TUE OCT 28 2014

QUIET WEATHER WILL BE THE RULE IN THE EARLY PART OF THE FORECAST
WITH SEASONABLE TEMPERATURES WEDNESDAY NIGHT AND MILD TEMPERATURES
THURSDAY.

AFTER THURSDAY...VERY COLD CANADIAN AIR FROM THE ARCTIC OCEAN
ISLANDS AREA WILL UNDERGO SOME MODIFICATION AS IT CROSSES THE
PRAIRIE PROVINCES AND ENTERS THE GREAT LAKES REGION AND THE UPPER
MIDWEST LATE THURSDAY NIGHT. BETWEEN THE CANADIAN AIR MASS AND A
DEVELOPING LEE SIDE TROUGH...THE PRESSURE GRADIENT WILL TIGHTEN
ENOUGH TO PRODUCE STRONG SOUTHEAST WIND FRIDAY...AND ESPECIALLY
SATURDAY...IN NEBRASKA. CURRENT INDICATIONS ARE THAT THE SOUTH TO
SOUTHEAST WIND WILL INCREASE BY LATE FRIDAY AFTERNOON TO 20-30 MPH
WITH GUSTS NEAR 40 MPH IN CENTRAL AND WESTERN NEBRASKA. THE DIURNAL
EFFECTS SHOULD BRING THE SPEED DOWN SOME FRIDAY NIGHT AND EARLY
SATURDAY. SOUTH TO SOUTHEAST WIND WILL THEN INCREASE AGAIN BY LATE
SATURDAY MORNING TO 25 TO 35 MPH WITH GUSTS AT OR ABOVE 45
MPH...ESPECIALLY IN CENTRAL AND EASTERN NEBRASKA.

TURNING TO TEMPERATURES FRIDAY...ALTHOUGH THE LOW LEVEL FLOW IS
SOUTH TO SOUTHEAST...THE TRAJECTORY OF THE AIR IS FROM THE UPPER
MISSISSIPPI VALLEY WHICH IS THE EXPECTED LOCATION OF THE COLDEST
ARCTIC AIR. AS A RESULT...THE SOUTH TO SOUTHEAST FLOW WILL RESULT IN
COLD ADVECTION OVER CENTRAL...SOUTH CENTRAL AND AT LEAST PART OF
SOUTHWEST NEBRASKA. THE STATISTICAL GFS GUIDANCE IS SHOWING
TEMPERATURES SIGNIFICANTLY COLDER THAN IT WAS IN THE PREVIOUS CYCLE.
THUS IT IS REASONABLE TO CONTINUE NUDGING THE TEMPERATURE FORECAST
FOR FRIDAY DOWNWARD. AS THE AIR MASS MOVES ON INTO THE OHIO
VALLEY...THE SOUTH FLOW WILL TAP THE WARMER AIR IN WEST TEXAS AND
TEMPERATURES WILL WARM SIGNIFICANTLY ON SATURDAY.

A FAIRLY STRONG FRONT IS EXPECTED TO CROSS NEBRASKA SUNDAY AND
SUNDAY NIGHT. SYSTEM-RELATIVE LIFT IS LIKELY THEN IN THE 305-315K
(700-500MB) LAYER WITH FAIRLY STRONG FRONTOGENESIS IN THAT LAYER.
THE UNDERLYING NEAR-SURFACE LAYER IS EXPECTED TO BE DRY WITH
RELATIVE HUMIDITY AT OR BELOW 40 PERCENT. HOWEVER...THE NEAR-SURFACE
LAYER IS LIKELY TO MOISTEN UP...AT LEAST IN NORTHERN NEBRASKA. THIS
WOULD PROVIDE A SMALL 6 HOUR WINDOW IN WHICH PRECIPITATION COULD
OCCUR BETWEEN MIDNIGHT SUNDAY NIGHT AND EARLY MONDAY.

RETURN FLOW MONDAY NIGHT WILL SET THE STAGE FOR SLIGHTLY WARMER
TEMPERATURES TUESDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1130 PM CDT TUE OCT 28 2014

VFR CONDITIONS THE NEXT 24 HRS FOR THE KLBF AND KVTN TERMINALS.
SKIES ARE CURRENTLY CLEAR AND ARE FORECAST TO REMAIN SO THROUGH
WEDNESDAY MORNING. LIGHT AND VARIABLE WINDS INTO WEDNESDAY
MORNING...THEN INCREASE SLIGHTLY TO NEAR 21008KT BY 18Z FOR BOTH
TERMINALS. ALSO SKIES BECOMING SCT TO BKN IN MID AND HIGH CLOUDINESS
TOWARD 00Z/30TH.

&&

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

$$

SYNOPSIS...MARTIN
SHORT TERM...MARTIN
LONG TERM...SPRINGER
AVIATION...ROBERG







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