Area Forecast Discussion
Issued by NWS North Platte, NE

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
000
FXUS63 KLBF 311204 AAA
AFDLBF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
704 AM CDT FRI OCT 31 2014

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 356 AM CDT FRI OCT 31 2014

MODELS IN FAIRLY GOOD AGREEMENT THIS MORNING COOL MODIFIED ARCTIC
HIGH PRESSURE 1039MB CONTINUES TO SURGE SOUTH ACROSS THE NORTHERN
PLAINS. THE CENTER OF THE HIGH IS OVER KDVL DEVILS LAKE NORTH
DAKOTA. BAND OF STRATUS FROM EASTERN MONTANA THROUGH WESTERN SOUTH
DAKOTA THROUGH CENTRAL NEBRASKA INTO SOUTHEAST NEBRASKA EARLY THIS
MORNING WILL CONTINUE TO MOVE SOUTHWEST ACROSS WESTERN NEBRASKA.
THIS IS HELPING TO MODERATE LOW TEMPERATURES SOME. MOISTURE IS
SHALLOW FROM THE SURFACE TO 850MB. LOW LEVEL MOISTURE WILL BUILD UP
ALONG SOUTHWEST NEBRASKA INTO THE NEBRASKA PANHANDLE WITH STRONG
SOUTHEAST FLOW PROVIDING UPGLIDE. HAVE SOME PATCHY FOG IN THE
FORECAST THROUGH MID MORNING WHEN STRATUS SHOULD BEGIN TO BREAKUP.
MOSTLY SUNNY THIS AFTERNOON. TEMPERATURES COOL OVER NORTH CENTRAL IN
KONL VICINITY...STRUGGLING INTO THE 40S. WARMER TO THE WEST AND
SOUTHWEST WITH HIGHS APPROACHING 50. CLEAR SKIES TONIGHT WITH
SOUTHERLY WINDS TO THE WEST AND LOW LEVEL JET WILL KEEP THINGS MIXED
BUT STRATUS TO REFORM OVER THE SOUTHEAST NEBRASKA PANHANDLE. BELIEVE
WITH THE STRONG SOUTHERLY FLOW WILL KEEP THINGS MIXED ENOUGH THAT
PATCHY FOG SHOULD NOT BE A PROBLEM. HAVE LEFT MENTION OF FOG OUT OF
THE FORECAST FOR TONIGHT. LOWS IN THE LOWER 20S ALONG THE PLATTE
RIVER VALLEY AND IN THE UPPER 20S TO AROUND 30 OVER THE REMAINDER OF
WESTERN NEBRASKA.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 356 AM CDT FRI OCT 31 2014

PRIMARY FORECAST CONCERNS DEAL WITH TEMPERATURES THROUGHOUT THE
PERIOD AND RAIN CHANCES SUNDAY NIGHT AND MONDAY.

MODELS ARE IN GOOD AGREEMENT FOR THE FIRST PART OF THE PERIOD AS
RIDGING IS IN PLACE OVERHEAD. ALTHOUGH THEY ARE COMING INTO BETTER
AGREEMENT WITH THE SYSTEM MOVING ACROSS THE REGION THROUGH THE
SUNDAY NIGHT MONDAY PERIOD...CONTINUE TO HAVE ENOUGH DISCREPANCIES
TO BRING LOWERED CONFIDENCE IN THE FORECAST IN THAT TIME FRAME. THEN
LOOKING THROUGH THE REMAINDER OF THE WEEK...THE MODELS HAVE THE SAME
GENERAL IDEA WITH THE EVOLUTION OF THE UPPER LEVEL PATTERN WITH A
LARGE UPPER LOW GETTING CUT OFF OVER NORTHERN MEXICO WHILE THE
NORTHERN AND CENTRAL PLAINS STAY UNDER THE INFLUENCE OF NORTHWEST
FLOW. THERE ARE DIFFERENCES IN TIMING AND STRENGTH OF WEAK SHORTWAVE
TROUGHS MOVING THROUGH THE FLOW DURING THE SECOND PART OF THE WEEK.
THEN LOOKING TOWARD THE WEEKEND MODEL DIVERGENCE CONTINUES AS THE
ECMWF AND GFS ARE EXHIBITING DIFFERENT IDEAS ON HOW TO HANDLE THE
SOUTHERN UPPER LEVEL LOW AS THE ECMWF TRIES TO PULL IT NORTH AND
INGEST IT INTO THE MEAN FLOW...WHILE THE GFS KEEPS IT CUT OFF OVER
TEXAS.

THE TEMPERATURE CHALLENGE BEGINS ON SATURDAY. DESPITE THE UPPER
LEVEL RIDGE BEING DIRECTLY OVERHEAD AND STRONG SOUTHERLY FLOW
EXPECTED ACROSS THE PLAINS...THERE WILL BE A BAND OF COOLER AIR
STILL IN PLACE OVER THE EASTERN HALF OF THE FORECAST AREA AROUND
850MB WHICH CONTINUES TO BE PULLED AROUND THE SURFACE HIGH /CENTERED
ALONG THE MISSISSIPPI RIVER VALLEY ON SATURDAY/. THIS COOLER AIR
WHICH WILL BE IN THE 1C TO 3C RANGE WILL LIMIT THE DEPTH OF MIXING
AND THUS THE RISE OF TEMPERATURES...NEGATING THE STRONG
INVERSION...WITH 750MB TEMPERATURES UP AT 11-14C. WHEN LOOKING AT
FORECAST SOUNDINGS...MIXING THE BOUNDARY LAYER BETWEEN 850MB AND
800MB WOULD PUT HIGHS IN THE 50S TO MID 60S. ALSO ON
SATURDAY...WINDS WILL BE FAIRLY STRONG AS THE PRESSURE GRADIENT WILL
BE TIGHT DUE TO THE POSITION OF THE SURFACE HIGH...WITH A DEVELOPING
SURFACE LOW PRESSURE SYSTEM OVER THE LEE SIDE OF THE ROCKIES.
SUSTAINED WINDS UP TO 20KTS ARE LIKELY...AND WITH WINDS AT THE TOP
OF THE MIXED LAYER RANGING FROM 30 TO 40KTS...COULD GET PERIODS OF
GUSTS NEARING 40 MPH AT THE SURFACE...ESPECIALLY OVER NORTH CENTRAL
NEBRASKA WHERE THE WINDS AT 850MB ARE STRONGEST.

THE WIND SHOULD STAY UP OVERNIGHT SATURDAY BUT BY 12Z SUNDAY MAY
BEGIN TO SUBSIDE OVER THE PANHANDLE AS THE SURFACE LOW BEGINS TO
MOVE CLOSER. THE WINDS WILL KEEP TEMPERATURES FROM DROPPING TOO FAR
OVERNIGHT. DIDN/T CHANGE MUCH FROM ONGOING FORECAST...WITH LOWS JUST
ABOVE NORMAL...IN THE 30S.

SUNDAY WILL BE THE WARMEST DAY OF THE WEEK AS THE RIDGE IS IN
BREAKDOWN MODE AS THE UPPER LEVEL TROUGH OVER THE WESTERN CONUS
PROGRESSES EAST. OVER THE WEEKEND THE TROUGH WILL SEE A SPLIT WITH
ONE PIECE OF ENERGY PULLING NORTH INTO MONTANA AND NORTH DAKOTA BY
00Z MONDAY...WHILE THE SECOND WILL DIG SOUTH INTO THE DESERT
SOUTHWEST. AS THIS OCCURS...THE FLOW WILL FINALLY PUSH OUT THE
COOLER AIR THAT HAD BEEN IN PLACE AT 850MB...WHICH WILL INCREASE TO
15-17C BY MID DAY SUNDAY AT THE SAME LEVEL. FORECAST SOUNDINGS SHOW
DEEP MIXING FOR MUCH OF THE AREA...UP TO AROUND 750MB WHICH WOULD
LEAD TO HIGHS IN THE UPPER 60S TO MID 70S. WITH THE MODELS IN GOOD
AGREEMENT WITH THIS OCCURRING...DID INCREASE TEMPERATURES A FEW
DEGREES FOR SUNDAY. ONE THING THAT COULD BE AN ISSUE THOUGH IS AN
INCREASE IN CLOUD COVER. CURRENT FORECAST HAS MOSTLY SUNNY
SKIES...BUT AS THE UPPER LEVEL TROUGH IS JUST OFF TO THE WEST COULD
SEE CIRRUS. MODELS AREN/T SHOWING A SIGNAL OF IT BEING TOO THICK BUT
IF THEY ARE WRONG AND THERE IS HIGHER CLOUD COVER TEMPERATURES COULD
BE IMPACTED. THE SURFACE FRONT WILL ALSO MOVE INTO WESTERN NEBRASKA
BY LATE SUNDAY...BUT THIS FRONT IS QUITE WEAK WITH THE TEMPERATURE
CONTRAST MINIMAL. THE STRONGER COLD FRONT WILL REMAIN UP OVER
MONTANA AND NORTH DAKOTA...ASSOCIATED WITH THE NORTHERN UPPER LEVEL
LOW.

THERE WILL LIKELY BE SEVERAL WAVES OF WEAK SHORTWAVE ENERGY MOVING
ACROSS THE FORECAST AREA BETWEEN SUNDAY NIGHT AND MONDAY NIGHT. THE
MODELS ARE SHOWING THE FIRST ONE OF SIGNIFICANCE EJECTING OUT OF THE
SOUTHERN SYSTEM AND PUSHING INTO NEBRASKA SUNDAY NIGHT. THE ECMWF IS
MUCH STRONGER WITH THIS ENERGY AT THIS TIME AND DEVELOPS A GOOD BAND
OF FRONTOGENESIS OVER NORTHWEST NEBRASKA AFTER 06Z. THE NAM AND GFS
HAVE THE SAME GENERAL SIGNALS BUT DELAYED A BIT WHICH BRING THIS
ENERGY ACROSS THE AREA DURING THE DAY MONDAY. AGAIN...ALL SHOW A
FAIRLY NARROW BAND ASSOCIATED WITH THE FRONTOGENETICAL FORCING WHICH
BEGINS OVER NORTHWEST NEBRASKA AND THE SANDHILLS THEN MIGRATES
SOUTHEAST. WHEN THE MODELS GET A BETTER HANDLE ON THE TIMING OF THIS
WILL NEED TO INCREASE PRECIPITATION CHANCES...BUT AT THIS TIME WITH
THE TIMING UNCERTAINTY DIDN/T WANT TO GO ABOVE CHANCE CATEGORY YET.
DID INTRODUCE A SLIGHT CHANCE FOR SHOWERS OVER THE FAR SOUTHEASTERN
COUNTIES INTO MONDAY EVENING AS THE MODELS ARE A BIT SLOWER THAN
PREVIOUS RUNS WITH THE EXITING OF THE SYSTEM.

IN ADDITION TO THE PRECIPITATION CHANCES...AS THE NORTHERN SYSTEM
PROGRESSES EAST THE COLD FRONT WILL PULL THROUGH NEBRASKA...WHICH
WILL BRING COOLER TEMPERATURES FOR THE FIRST PART OF THE WORK WEEK.
HIGHS MONDAY AND TUESDAY LOOK TO BE IN THE 50S...BUT THE INCLUSION
OF CLOUDS AND PRECIPITATION ALL DAY MONDAY COULD LEAD TO COOLER
CONDITIONS. MODERATING TEMPERATURES ARE ANTICIPATED THEN FOR THE END
OF THE WEEK AS RIDGING BUILDS BACK IN. THE FORECAST IS CURRENTLY DRY
WITH ABOVE NORMAL TEMPERATURES FOR WEDNESDAY THROUGH FRIDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 704 AM CDT FRI OCT 31 2014

A STRATUS DECK LIES FROM THE NORTHERN NEBRASKA PANHANDLE THROUGH
SOUTH CENTRAL NEBRASKA. THERE WERE SOME AREAS OF FOG ALONG THE
LEADING EDGE OF THE STRATUS ALONG A LINE FROM CHADRON TO OGALLALA
TO IMPERIAL...WITH IFR VISIBILITIES FROM 1 TO 3SM. THE AREA OF
STRATUS WAS MOVING TO THE SOUTHWEST AND AT PRESENT WAS TO THE WEST
OF A LINE FROM KVTN TO KODX...CEILINGS RANGED FROM OVC002 AT KOGA
TO OVC016 AT KBBW. THE AREA OF STRATUS WILL CONTINUE TO MOVE WEST
THROUGH THE MORNING WEST OF A LINE FROM KVTN TO KLBF BEFORE
STALLING OUT AND THEN SLOWLY ERODING THIS MORNING.

&&

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

$$

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






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.