Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 301148 AAA
AFDLBF

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

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 354 AM CDT THU OCT 30 2014

UPPER LOW OVER HUDSON BAY EARLY THIS MORNING WITH MID LEVEL WAVE
MOVING INTO WESTERN IOWA. LIGHT SHOWERS FROM SOUTHWEST MINNESOTA TO
SOUTHEAST NEBRASKA. STRONG UPPER LOW OVER THE GULF OF ALASKA WITH
SHARPENING RIDGE OVER THE WESTERN CONUS...PLACING NORTHERN PLAINS IN
NORTHWEST FLOW ALOFT. MODELS IN GOOD AGREEMENT IN THE NEAR TERM WITH
HUDSON BAY LOW DRIVING A MODIFIED ARCTIC AIRMASS SOUTH ACROSS THE
NORTHERN PLAINS. LEADING EDGE OF COLD FRONT OVER SOUTHERN NORTH
DAKOTA AND MONTANA. THIS FRONT WILL MOVE SOUTH TODAY ACROSS WESTERN
NEBRASKA. TEMPERATURES IN THE LOW 30S WITH SNOW IN SOUTH CENTRAL
CANADA. COLDEST AIR IN NORTHERN SASKATCHEWAN AND MANITOBA SINGLE
DIGITS AND TEENS. TEMPERATURES WILL RANGE FROM THE LOW 50S NORTH TO
THE LOW 60S SOUTH TODAY WITH FULL SUN. BREEZY NORTHWEST WINDS WILL
ACCOMPANY THE FRONTAL PASSAGE. BOUNDARY LAYER WILL REMAINED MIXED
OVER NIGHT WITH NORTH FLOW WHICH WILL HELP TO KEEP TEMPERATURES UP
SOME. A RELATIVELY NARROW BAND OF STRATUS WILL PUSH SOUTHWEST ACROSS
WESTERN NEBRASKA OVER NIGHT AND WILL HELP TO KEEP TEMPERATURES UP
OVER THE WEST AS 850MB TEMPERATURES FALL TO AROUND 0C BY 31/12Z.
HAVE TEMPERATURES FALLING INTO THE LOW 20S OVER NORTH AND NORTH
CENTRAL NEBRASKA WITH MID AND UPPER 20S SOUTH AND WEST WITH MORE
CLOUD COVER.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 354 AM CDT THU OCT 30 2014

FORECAST CONCERNS ARE TEMPERATURES THROUGHOUT THE PERIOD...AS WELL
AS PRECIPITATION CHANCES SUNDAY NIGHT AND MONDAY.

FRIDAY MORNING BEGINS WITH HIGH PRESSURE CENTERED OVER THE EASTERN
DAKOTAS. WITH THE EXCEPTION OF SHALLOW MOISTURE BEING SEEN BY BOTH
THE NAM AND GFS BEING PULLED AROUND THE BACK SIDE OF THE SURFACE
HIGH INTO WESTERN NEBRASKA THE AIRMASS ACROSS THE NORTHERN AND
CENTRAL PLAINS IS QUITE DRY WITH RELATIVE HUMIDITY THROUGH THE
REMAINDER OF THE LAYER BEING GENERALLY LESS THAN 40 PERCENT. LOOKING
AT FORECAST SOUNDINGS...IT DOES LOOK LIKE SURFACE WINDS STAY HIGH
ENOUGH TO KEEP THE FAR LOW LEVELS MIXED TO THE POINT THAT DON/T
BELIEVE FOG WILL BE AN ISSUE. ALSO...THE MOISTURE TRAPPED UNDER THE
INVERSION LOOKS DEEP ENOUGH FOR THE INCLUSION OF STRATUS FRIDAY
MORNING MAINLY WEST OF A LINE FROM MERRIMAN TO NORTH PLATTE SO WILL
INCREASE SKY COVER FOR THESE AREAS.

THE BOUNDARY LAYER DOES MIX OUT BY 18Z SO CLOUD COVER SHOULD
DIMINISH BY LATE MORNING WITH THE VERY DRY AIRMASS TAKING OVER
LEADING TO MOSTLY SUNNY SKIES. THERE MAY BE A LITTLE CIRRUS MOVE
ACROSS THE STATE FRIDAY AFTERNOON...BUT IT DOESN/T LOOK TO BE REAL
THICK SO AGAIN KEEPING THE MOSTLY SUNNY SKIES IN THE FORECAST. EVEN
WITH THE SUNSHINE...LOOKING AT BELOW NORMAL TEMPERATURES FOR FRIDAY
AS THE AIRMASS ASSOCIATED WITH THE SURFACE HIGH IS NOT ONLY VERY
DRY...BUT QUITE COLD. THE SURFACE HIGH WAS SITUATED OVER THE
NORTHWEST TERRITORIES IN CANADA ON WEDNESDAY AFTERNOON WHERE HIGHS
ONLY IN THE TEENS AND 20S. THE AIRMASS WILL MODERATE AS IT MOVES
SOUTH OVER THE NEXT 35 HOURS...BUT WITH THE MODELS ALL SHOWING 850MB
TEMPERATURES BELOW 3C ACROSS THE ENTIRE FORECAST AREA HIGHS IN THE
40S TO LOW 50S ARE LOOKING APPROPRIATE.

BY SATURDAY THE UPPER LEVEL PATTERN IS QUITE AMPLIFIED WITH RIDGING
DIRECTLY OVERHEAD SPANNING THROUGH THE PLAINS...WITH DEEP TROUGHS
OVER BOTH THE EAST COAST AND THE WEST COAST. SOUTHERLY FLOW IN THE
LOW LEVELS WILL PICK UP THROUGH THE DAY AS A VAST AREA OF LOW
PRESSURE DEVELOPS OVER THE ROCKIES AHEAD OF THE UPPER LEVEL TROUGH
AND HIGH PRESSURE STAYS IN PLACE OVER THE MISSISSIPPI RIVER VALLEY.
THIS PATTERN WILL ALLOW FOR THE GULF TO OPEN UP AND ALLOW MOISTURE
TO START FUNNELING NORTHWARD THROUGH THE PLAINS. WARM AIR ADVECTION
WILL BE ONGOING THROUGH THE DAY...BUT IN AREAS OVER CENTRAL AND
EASTERN NEBRASKA THE COOLER AIR WILL BE SLOW TO BE PUSHED OUT AS THE
SURFACE HIGH MOVES EASTWARD ONLY SLIGHTLY THROUGH THE DAY. SO
THINKING TEMPERATURE GRADIENT WILL BE DECENT ACROSS THE FORECAST
AREA WITH THE EASTERN AREAS SEEING HIGHS AROUND 50...WHILE PARTS OF
THE PANHANDLE AND FAR SOUTHWEST NEBRASKA WILL GET INTO THE UPPER
60S. ALSO DUE TO THE LACK OF MOVEMENT OF THE SURFACE HIGH...THE
PRESSURE GRADIENT WILL TIGHTEN SIGNIFICANTLY BY SATURDAY AFTERNOON.
CURRENTLY THINKING SUSTAINED WINDS WILL BE IN THE 15 TO 25 MPH
RANGE...PERHAPS NEARING 30 MPH OVER NORTH CENTRAL NEBRASKA. WHAT
GUSTS WILL GET TO IS STILL UNCERTAIN. MODEL SOUNDINGS ARE SHOWING
MIXING TO AROUND 850MB. THERE ARE DIFFERENCES IN HOW STRONG THE
WINDS WILL BE AT THAT LEVEL...BUT AGAIN THE STRONGER WINDS ARE MORE
LIKELY OVER NORTH CENTRAL NEBRASKA. COULD GET GUSTS NEAR 40 MPH IN
THOSE AREAS.

MOVING INTO THE FIRST PART OF NEXT WEEK...THERE IS SOME AGREEMENT
WITH THE GENERAL PROGRESSION OF THE WESTERN TROUGH...HOWEVER VAST
DIFFERENCES REMAIN AS THE NEWEST 30.00Z MODEL RUNS HAVE COME IN TO
KEEP A FAIR AMOUNT OF UNCERTAINTY IN THE FORECAST. IT DOES LOOK LIKE
THE TROUGH WILL SPLIT WITH ONE PIECE OF ENERGY MOVING UP INTO THE
DAKOTA/S THROUGH MONDAY THEN SLOWLY MIGRATE EAST ACROSS SOUTHEAST
CANADA THROUGH THE END OF THE WEEK. MEANWHILE A SECOND PIECE OF
ENERGY WILL STAY SOUTH AND DIG INTO MEXICO AND THEN TRAVEL ACROSS
TEXAS. IN THE MEANTIME...THE GFS AND GEM AND VERY DISCRETELY IN THE
ECMWF DO PUSH A SHORTWAVE TROUGH UP FROM THE BASE OF THE TROUGH
WHICH EVENTUALLY JOINS UP WITH THE NORTHERN UPPER LOW. THIS ENERGY
WOULD PASS DIRECTLY OVER THE FORECAST AREA SUNDAY NIGHT AND MONDAY.
THIS WOULD COINCIDE WITH THE PASSAGE OF THE SURFACE COLD FRONT.
CROSS SECTIONS DO SHOW INCREASING MOISTURE OVER THE FORECAST AREA AS
THIS ALL OCCURS WITH THE HIGHER AMOUNTS OF OMEGA SEEN IN THE WAKE OF
THE SURFACE FRONT. ALTHOUGH PRECIPITATION AMOUNTS DON/T LOOK
SIGNIFICANT...CHANCES FOR RAIN CERTAINLY LOOK WARRANTED FROM SUNDAY
NIGHT INTO THE DAY MONDAY. THESE CHANCES WILL WANE AS THE DAY
PROGRESSES MONDAY.

LOOKING AT THE REMAINDER OF NEXT WEEK...THE CURRENT FORECAST IS DRY
WITH NO SIGNIFICANT SYSTEMS IN PLAY. THAT BEING SAID...THERE ARE
PLENTIFUL DIFFERENCES IN THE LARGE SCALE PATTERN TO LEAD TO LOWER
CONFIDENCE IN THE OUTER PERIODS OF THIS FORECAST CYCLE. AT THIS
TIME...WILL KEEP TEMPERATURES NEAR NORMAL...WITH A SLIGHT INCREASE
BY LATE IN THE WEEK AS THERE ARE INDICATIONS OF ANOTHER RIDGE
BUILDING IN ACROSS THE CENTRAL PART OF THE COUNTRY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 648 AM CDT THU OCT 30 2014

A COLD FRONT WILL MOVE SOUTH ACROSS NEBRASKA TODAY WITH STRONG
NORTH WINDS AND MOSTLY CLEAR SKIES. STRATUS WITH MVFR CEILINGS IS
EXPECTED TO MOVE ACROSS WESTERN NEBRASKA AFTER MIDNIGHT.

&&

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

$$

SHORT TERM...POWER
LONG TERM...BROOKS
AVIATION...POWER







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