Area Forecast Discussion
Issued by NWS North Platte, NE

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000
FXUS63 KLBF 132327
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
527 PM CST SAT FEB 13 2016

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 339 PM CST SAT FEB 13 2016

THE MAIN FORECAST CHALLENGE THROUGH SUNDAY EVENING IS THE OVERALL
FORECAST SCENARIO...WITH CLOUD COVER... TEMPERATURES...
PRECIPITATION... AND WIND BEING ESPECIALLY INTER RELATED TONIGHT.
RATHER COMPLEX SITUATION WITH A SURFACE FRONT IN THE NEBRASKA
PANHANDLE...QUICK MOVING AND RATHER STOUT SHORTWAVE ACROSS THE NORTH
OVERNIGHT AND THE 250HPA JET IN THE VICINITY. LOW CLOUDS HAVE HUNG
AROUND ALL DAY WITH PERIODS OF FREEZING DRIZZLE AND FOG THIS
MORNING...WITH MIST/DRIZZLE ENDING BY 18Z FOR MOST OF THE AREA.
GUSTY SOUTH WINDS HAVE SURPASSED 30 KTS FAR NORTH...INCLUDING KVTN.

CLOUD COVER...SHOULD SLOWLY DECREASE PANHANDLE AND SOUTHWEST
NEBRASKA TONIGHT AS MID LEVEL DRY AIR WORKS ITS WAY TOWARD THE
SURFACE. AS OF 21Z...THE EDGE OF THE LOW CLOUDS WAS JUST WEST OF NEB
HWY 61 WITH SOME MID/HIGH CLOUDS REMAINING. MAINTAINED COVER
OVERNIGHT NORTH AND EAST WITH THE PASSAGE OF THE SHORTWAVE.
INCREASED CLOUDS AGAIN SUNDAY AFTERNOON AHEAD OF ANOTHER WAVE.

WIND...SPEEDS SHOULD STAY ELEVATED THROUGH THE NIGHT WITH THE FROPA
AND SHORTWAVE DRAGGING SOME 850HPA WINDS TOWARD THE SURFACE.
ECM...NAM...AND GFS INDICATING 850HPA WINDS 40 TO 50 KTS...BUT WITH
A SFC INVERSION IN PLACE AREA-WIDE AND PERSISTENT CLOUDS
EAST...NOT EXPECTING THE FULL FORCE. TRANSITION FROM SOUTH TO
NORTHWEST WITH FROPA AROUND 06Z.

TEMPS...LOOKING AT A NON DIURNAL TREND WITH STEADY/RISING TEMPS
THROUGH SUNDAY MORNING. STRONG WAA TAKING PLACE AT 850HPA WITH TEMPS
RISING FROM -7C AT 18Z SAT TO 2C BY 12Z SUNDAY FOR MOST OF THE AREA.
MIN TEMPS OCCUR EARLY WITH 20S CENTRAL NEB AND NEAR 30 ALONG/WEST OF
HWY 83. EARLY CLOUD BREAKS...MILDER 850HPA TEMPS...AND DOWNSLOPING
WINDS WILL CONTRIBUTE TO MAX TEMPS IN THE 40S AND LOWER 50S SUNDAY.
MOS GUIDANCE TRENDED SLIGHTLY WARMER...AND UPPED HIGHS A DEGREE OR
SO DUE TO AFOREMENTIONED REASONS. DID TREND DOWN SLIGHTLY IN BOYD
COUNTY FOR POSSIBLE OVERNIGHT LIGHT SNOW ACCUMULATION.

PRECIP...FRONTOGENESIS LOOKS GOOD REGION-WIDE AND ISENTROPIC
UPGLIDE AT 280K AND 290 IS EVIDENT ACROSS THE SANDHILLS.
HOWEVER...THE BEST MOISTURE PROFILES ARE GENERALLY NORTH OF HWY 2
AS MID AND LOW LEVEL DRY AIR WORKS INTO THE PANHANDLE AND
SOUTHWEST NEBRASKA. TEMP PROFILES IN FORECAST SOUNDINGS SHOW RAIN
TO BEGIN WITH...SO INTRODUCED -RA FOR AREAS WITH SFC TEMPS GE 37F
AND RASN GE 35F EARLY SAT EVENING. TRANSITIONED ALL PRECIP TO SNOW
AFTER 06Z AS THE WARM WEDGE DISAPPEARS. NAM CROSS SECTIONS SHOW
DECENT LIFT COLOCATED WITH SATURATION NORTH OF KONL...ALONG WITH
SOME FOLDED THETA E. INCREASED QPF AS A HEAVIER SNOW SHOWER MAY BE
POSSIBLE ACROSS NORTHERN HOLT AND BOYD COUNTIES. HOWEVER...THE DGZ
LIES WELL ABOVE THE BEST LIFT...WITH WILL CUT DOWN ON SLR.
OVERALL...ACCUMULATION WILL LIKELY STAY UNDER ONE INCH AS THE
WINDOW FOR BEST FORCING IS RATHER SHORT...GENERALLY 03-09Z.

OTHER CONCERNS...SREF IS SHOWING A WEAK SIGNAL OF FOG ALONG THE EDGE
OF THE STRATUS TONIGHT...ROUGHLY ALONG/WEST OF HWY 83. ALTHOUGH A
NON ZERO CHANCE OF FOG REDEVELOPMENT...BREEZY WINDS AND THE TIMING
OF MID/LOW LEVEL DRY AIR LOWER MY CONFIDENCE. LEFT MENTION OUT OF
THIS FORECAST PACKAGE...BUT MAY HAVE TO BE WATCHED FOR LATER
ADDITION.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 339 PM CST SAT FEB 13 2016

00Z MONDAY AND BEYOND.  THE PRIMARY FORECAST CHALLENGE IN THE
EXTENDED WILL BE TEMPERATURES...MORE SPECIFICALLY HOW WARM
TEMPERATURES GET MID-WEEK.  A SECONDARY CONCERN IS THE POTENTIAL OF
LIGHT QPF LATE SUNDAY NIGHT...AND POSSIBLY AGAIN TUESDAY MORNING.

THE PRECIPITATION CHANCES ARE TIED TO A SERIES OF QUICK MOVING
SHORTWAVE DISTURBANCES.  THE FIRST OF WHICH WILL ARRIVE SUNDAY
AFTERNOON AND EXIT RAPIDLY TO THE SOUTH BY EARLY MONDAY MORNING.
THE LATEST GUIDANCE REMAINS FIXED THAT THE BEST MOISTURE AND FORCING
FOR PRECIPITATION WITH THIS SYSTEM REMAINS TO THE WEST OF THE
CWA...HOWEVER THE MODELS SHOW A BRIEF PERIOD WHEN TOP DOWN
SATURATION OCCURS WHILE OMEGA IS PRESENT ACROSS SOUTHWEST AND NORTH
CENTRAL NEBRASKA. THERMAL PROFILES NEAR THE SURFACE ARE LARGELY
ABOVE 0C...SO THE PRIMARY MODE SHOULD BE RAIN...HOWEVER GIVEN THE
TIME OF DAY /EVENING/...WILL GO WITH A RAIN AND/OR SNOW MIX. FOR NOW
WILL ONLY CARRY A SLIGHT CHANCE MENTION AS THE MOISTURE QUICKLY
SCOURS OUT AND OMEGA WANES WITH THE FAST PROGRESSION OF THE SYSTEM.

THE NEXT WAVE OF INTEREST ARRIVES ACROSS THE NORTHERN PLAINS MONDAY
AFTERNOON AND EVENING.  PROXIMITY SOUNDINGS FROM NORTH CENTRAL
NEBRASKA AND THE SANDHILLS INDICATE TEMPERATURES WILL BE WARM ENOUGH
FOR RAIN...WITH SNOW CHANCES HOLDING OUT UNTIL AFTER 06Z TUESDAY.
THE MODELS INDICATE A WEAK CONVECTIVE ELEMENT WITH THIS
SYSTEM...RAIN SHOWERS WILL BE THE PRIMARY MODE.  ANOTHER WEAK
DISTURBANCE DROPS THROUGH 24 HOURS LATER...BRINGING THE POTENTIAL OF
LIGHT QPF TO NORTH CENTRAL NEBRASKA...HOWEVER THE BETTER FORCING
AND MOISTURE ONCE AGAIN IS NORTH OF THE CWA...SO WILL GO WITH A
DRY FORECAST FOR NOW AND MONITOR. ALL IN ALL...PRECIP CHANCES IN
THE EXTENDED ARE SLIGHT AT BEST...WITH ONLY LIGHT QPF EXPECTED
WHERE PRECIP OCCURS.

A WARMING TREND IS FORECAST FOR THIS COMING WEEK...MAINLY DUE
TO STRONG WAA AND DOWNSLOPING WINDS FROM THE WEST. H85
TEMPERATURES BY 00Z THURSDAY WILL REACH INTO THE UPPER TEENS TO
LOW 20S ACROSS SOUTHWEST NEBRASKA AND THE EASTERN PANHANDLE.
HIGHS WELL INTO THE 60S ARE FORECAST BY THURSDAY...WITH THE
POSSIBILITY OF LOWER 70S ACROSS SOUTHWEST NEBRASKA THURSDAY
AFTERNOON. THE RIDGE RESPONSIBLE FOR THE ABOVE AVERAGE
TEMPERATURES BREAKS DOWN THURSDAY AFTERNOON...WITH A STRONG COLD
FRONT TO FOLLOW DURING THE THURSDAY EARLY MORNING FRIDAY TIME
PERIOD. OUTSIDE OF THE OVERNIGHT FRONTAL PASSAGE...AND THE FACT
WE EXPERIENCED IN SOME CASES NEAR RECORD SNOWFALL A LITTLE OVER A
WEEK AND A HALF AGO...THIS PATTERN FAVORS LARGE RANGE FIRE
GROWTH. WILL CONTINUE TO MONITOR HOW THE MELTING SNOWPACK PLAYS
OUT...FUELS ARE CURED AND IT WOULDN/T TAKE MUCH FOR THEM TO
PROMOTE LARGE FIRE GROWTH...ESPECIALLY IN AREAS THAT DID NOT SEE
THE HEAVY SNOWS /ZONES 204 AND 208/.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 525 PM CST SAT FEB 13 2016

INCREASING CEILING IS EXPECTED TO CONTINUE WITH AT LEAST VISUAL
METEOROLOGICAL IN SOUTHWEST NEBRASKA BY 03Z AND IN NORTHERN
NEBRASKA BY 05Z. WIND ALOFT WILL INCREASE AND BECOME 32040KT AT
1500-2000 FEET AGL. IN THE NORTH...WIND WILL MIX DOWN TO THE
SURFACE AND...AFTER SUBTRACTING FOR FRICTION...WILL BECOME 280-300
AT 14-18KT AND POSSIBLY GUSTING OVER 22KT. IN THE SOUTHWEST...
PRIMARILY IN THE NORTH PLATTE RIVER VALLEY...THE SURFACE WIND
WILL PROBABLY BE 10KT OR LESS FROM 280-300 WITH 33040KT JUST ABOVE
THE SURFACE LAYER. THEREFORE...WE HAVE INCLUDED LOW LEVEL WIND
SHEAR IN THE FORECAST FOR LBF.

&&

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

$$

SHORT TERM...SNIVELY
LONG TERM...JACOBS
AVIATION...SPRINGER


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