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000
FXUS63 KLBF 210901
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
401 AM CDT MON APR 21 2014

.SYNOPSIS...
ISSUED AT 357 AM CDT MON APR 21 2014

H5 ANALYSIS FROM EARLIER THIS EVENING HAD A CLOSED LOW OFF THE
COAST OF THE CAROLINAS...WITH A TANDEM OF SHORTWAVE TROUGHS
ACROSS THE CENTRAL CONUS. THE FIRST SHORTWAVE WAS LOCATED OVER
KANSAS WITH A SECOND NRN STREAM SHORTWAVE OVER SERN SASKATCHEWAN
AND SWRN MANITOBA. THE NORTHERN STREAM WAVE HAS FORCED A COLD
FRONT THROUGH THE FORECAST AREA OVER THE PAST 1 TO 3 HOURS. SOME
SHOWERS AND THUNDERSTORMS LIT UP ALONG THE FRONT EARLIER WITH THE
BEST COVERAGE OVER PORTIONS OF THE NORTHEASTERN AND EASTERN
CWA...OR ROUGHLY ALONG A LINE FROM ONEILL...TO STAPLETON TO NORTH
PLATTE. COVERAGE WAS ISOLATED TO WIDELY SCATTERED AT BEST...SO
PRECIPITATION AMOUNTS WERE RELATIVELY LIGHT. THIS AREA OF SHOWERS
AND THUNDERSTORMS HAS SLID TO THE SOUTHEAST OF THE AREA AND WAS
NOW IMPACTING SOUTH CENTRAL THROUGH EAST CENTRAL NEBRASKA AS OF 3
AM CDT. AS OF 3 AM CDT...WITH THE EXCEPTION OF FAR EASTERN AREAS
OF THE FORECAST AREA...SKIES WERE CLEAR WITH TEMPERATURES RANGING
FROM 52 DEGREES AT VALENTINE...TO 55 DEGREES AT NORTH
PLATTE...THEDFORD...ONEILL...IMPERIAL...OGALLALA AND BROKEN BOW.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 357 AM CDT MON APR 21 2014

OVER THE NEXT 24 HOURS...TEMPERATURES AND THE INCREASED FIRE
DANGER THREAT ARE THE MAIN FORECAST CHALLENGES. FOR
TODAY...DECENT NORTHERLY WINDS WILL CONTINUE THROUGH
MIDDAY...SLOWLY DIMINISHING INTO THE LATE AFTERNOON AND EVENING
HOURS. FCST SOUNDINGS ARE INDICATING DECENT MIXING UP TO 800MB
THIS AFTERNOON. WITH 21Z H85 FCST TEMPS RANGING FROM 9C IN THE
NORTHEAST...TO 14C IN THE SOUTHWEST...MID AND UPPER 60S LOOK LIKE
A SAFE BET FOR HIGHS...HOWEVER...WITH MIXING ABOVE THE 850MB
LEVEL EXPECTED...WILL ADD 2 TO 4 DEGREES TO THESE READINGS
RESULTING IN HIGHS IN THE UPPER 60S TO LOWER 70S. THE NORTHERLY
FLOW WILL ALSO USHER IN SOME MUCH DRIER AIR FROM THE DAKOTAS WITH
DEW POINTS IN THE UPPER 20S TO AROUND 30 DEGREES THIS
AFTERNOON...RESULTING IN SOME MINIMUM RELATIVE HUMIDITIES OF 20
TO 25 PERCENT LATER TODAY. FOR NOW...DECIDED TO FORGO A RED FLAG
WARNING IN THE NORTHEAST AND EASTERN ZONE (NEZ209) THIS
AFTERNOON. MINIMUM RH`S WILL BE CLOSE TO WARNING
CRITERIA...HOWEVER...WINDS WILL PEAK AROUND MIDDAY...THEN SLOWLY
DECREASE INTO THE AFTERNOON HOURS AND ARE EXPECTED TO BE BELOW
THE 25 MPH CRITERIA DURING PEAK HEATING. EVEN WITHOUT RED FLAG
CRITERIA...FIRE DANGER WILL BE EXTREME TODAY...ESPECIALLY EAST OF
HIGHWAY 83 AND WILL HIT THIS HARD IN THE HWO. FOR TONIGHT...WINDS
WILL SHIFT TO THE SOUTH...HOWEVER...LOW LEVEL MOISTURE ADVECTION
IS EXPECTED TO BE WEST OF THE AREA OVER EASTERN COLORADO. DEW
POINTS WILL REMAIN IN THE LOWER 30S TONIGHT...ALLOWING LOWS TO
DROP INTO THE LOWER TO MIDDLE 30S UNDER MOSTLY CLEAR SKIES.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 357 AM CDT MON APR 21 2014

TUESDAY WILL SEE A UPPER LEVEL TROUGH MOVE ACROSS THE PACIFIC NW.
RIDGING AHEAD OF THE TROUGH WILL CAUSE 850 MB TEMPS TO WARM INTO
THE TEENS FOR MOST AREAS. RIDGE AXIS IS ACROSS THE ROCKIES WITH
WARMEST TEMPS /NEAR 80/ ACROSS THE WESTERN ZONES. STILL IN THE
LOWER TO MID 70S ACROSS THE EAST. LEE SIDE TROUGH DEVELOPS DURING
THE DAY WITH THE NAM AND EC KICKING OFF SOME AFTERNOON
THUNDERSTORMS. IMPACT WILL BE PRIMARILY TO THE WEST...ALTHOUGH THE
FAR WESTERN ZONES WILL CONTINUE TO SEE LOW CHANCE FOR
THUNDERSTORMS. AN UPPER LEVEL DISTURBANCE WILL GET KICKED ACROSS
THE AREA TUESDAY NIGHT...AHEAD OF THE MAIN TROUGH. THIS WAVE MAY
COMBINE WITH THE SFC TROUGH FOR MORE ROBUST THUNDERSTORM
DEVELOPMENT...ALTHOUGH EXPECT THE LIMITED MOISTURE TO BE THE
LIMITING FACTOR AND KEEP MOST OF THE ACTIVITY IN A ISOLD TO SCT
NATURE. HOWEVER AS THE WAVE MOVES EAST /ACROSS THE FORECAST AREA/
OVERNIGHT A LLJ INCREASES TO OVER 50 KTS. THIS SHOULD BE ABLE TO
SUSTAIN/EXPAND THUNDERSTORM ACTIVITY. MODELS ARE IN GOOD
AGREEMENT...EVEN THE GFS JOINS THE PARTY...WITH ELEVATED ACTIVITY
TO IMPACT THE AREA. NEG LI/S AND LOW CAPE SHOULD RESULT IN SOME
THUNDER ALTHOUGH SHEAR IS WEAK AND BASES FAIRLY HIGH AND DECENT
SPEED WILL KEEP QPF AMOUNTS ON THE LOW SIDE.

WEDNESDAY IS BECOMING MORE INTERESTING...AND LESS CONFIDENCE AS
MODEL SPREAD INCREASE. THE UPPER LEVEL LOW MOVES TOWARDS THE
NORTHERN PLAINS...AS A SFC COLD FRONT WILL PUSH THROUGH THE HIGH
PLAINS. TIMING OF THIS FRONT VARIES FROM A FAST GFS TO A SLOW NAM
BY SEVERAL HOURS. THIS IS CRITICAL AS VERY WARM AIR AHEAD OF THE
FRONT WITH THUNDERSTORMS...SOME SEVERE...EXPECTED ALONG AND AHEAD
OF THE FRONT. EARLY IN THE DAY 850 MB TEMPS NEAR OR ABOVE
20C...AHEAD OF THE FRONT...WHICH SHOULD MIX DOWN AND PUSH HIGHS
WELL INTO THE 70S WITH SEVERAL SITES ABOVE 80. THEN EXPECT THE
DEVELOPMENT OF A LINE OF SEVERE THUNDERSTORMS. THE SLOWER MODELS
HAVE DEVELOPMENT NEAR HIGHWAY 83...WHILE THE REST ARE FURTHER
EAST.

BEHIND THE COLD FRONT WILL BE COOLER CONDITIONS...60S. A
SECONDARY WAVE ROTATES AROUND UPPER LEVEL THE LOW AS IT PUSHES
TOWARDS THE GREAT LAKES. WILL NOT HAVE MUCH MOISTURE TO WORK
WITH...AS SOURCE WILL BE PACIFIC.

BY FRIDAY INTO THE WEEKEND MODELS CONTINUE TO SHOW ONLY MEAGER
AGREEMENT. A TROUGH WILL PUSH ONTO THE WEST COAST...THEN ACROSS
THE PLAINS. THE ECMWF HAS A MUCH FURTHER NORTH TRACK AND WOULD
EXPECT LESS PRECIP CHANCES FOR OUR AREA WITH THIS SET UP. THE GFS
IS A MORE FAVORABLE SOUTHERN TRACK AND BRINGS SOME BANDED PRECIP
TO THE AREA. ONE AGREEMENT IS A TREND TOWARDS COLDER TEMPS
ALTHOUGH THE GFS IS COLDER...WHICH IS NOT SURPRISING GIVEN THE
FURTHER SOUTH TRACK. THE UPPER LEVEL LOW OVER THE GREAT
LAKES...WHICH MODELS HAVE DECENT AGREEMENT ON...TAPS SOME COLD
CANADIAN AIR AND DRAWS IT SOUTH OVER THE NORTHERN AND CENTRAL
PLAINS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1229 AM CDT MON APR 21 2014

SCATTERED THUNDERSTORMS WILL CONTINUE TO MOVE TO THE SOUTHEAST OVER
WESTERN NEBRASKA EAST OF A LINE FROM KVTN TO KLBF THROUGH THE EARLY
MORNING HOURS. LIMITED LOW LEVEL MOISTURE SO BASES ON THUNDERSTORMS
AROUND 8K FT. STRONG GUSTY OUT FLOW CAN BE EXPECTED ALONG AND BEHIND
THIS LINE WITH GUST 25 TO 30 KTS. SKIES WILL CLEAR THROUGH THE EARLY
MORNING HOURS WITH NORTH WINDS DIMINISHING SOME BEFORE PICKING BACK
UP THROUGH THE LATE MORNING AND AFTERNOON ON MONDAY.


&&

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

&&

$$

SYNOPSIS...CLB
SHORT TERM...CLB
LONG TERM...MASEK
AVIATION...POWER