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000
FXUS63 KLBF 280913
AFDLBF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
313 AM CST FRI FEB 28 2014

.SYNOPSIS...
ISSUED AT 311 AM CST FRI FEB 28 2014

THE 08Z MSL ANALYSIS SHOWED LOW PRESSURE CENTERED OVER EASTERN
WYOMING AND OVER THE COLORADO-NEW MEXICO-OKLAHOMA-KANSAS
INTERSECTION. A STATIONARY FRONT WAS DRAPED FROM THE WYOMING LOW
SOUTH ALONG THE HIGH PLAINS TO WESTERN KANSAS WITH A COLD FRONT
ACROSS WYOMING TO SOUTHWEST MONTANA AND THE IDAHO PANHANDLE. IN THE
UPPER LEVELS...WATER VAPOR IMAGERY INDICATED A COMMA OVER THE
TEXAS-NEW MEXICO BORDER. FARTHER OUT...THERE WAS AN OCCLUDING
CYCLONE OVER THE PACIFIC NEAR 37.4N/133.2W.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 311 AM CST FRI FEB 28 2014

TODAY...A FRONT PLUNGES THROUGH WESTERN NEBRASKA AND THEN STALLS
ACROSS KANSAS BEFORE LIFTING BACK NORTH WITH RETURN FLOW TONIGHT. AS
THE FRONT COMES SOUTH...SOME SURGE IN TEMPERATURE CAN BE EXPECTED
ALONG AND SOUTH OF THE FRONT. ALSO...SYSTEM RELATIVE LIFT WILL
PRODUCE A FEW SHOWERS. THE LIFT AND NEAR SATURATION REACH INTO THE
DENDRITIC LAYER AND THE LOWEST 1-2KM IS COLD ENOUGH THAT WHAT DOES
REACH THE SURFACE WILL BE SNOW.

MUCH BETTER LIFT IS EXPECTED TONIGHT AS THE RETURN FLOW LIFTS THE
SATURATED AIR THROUGH THE 290-310K LAYER WHICH INCLUDES THE
DENDRITIC LAYER. A NORTHEAST-SOUTHWEST CROSS-SECTION SHOWS SOME
HYDROSTATIC INSTABILITY WITH A FOLDED THETA-E PROFILE IN THE
295-305K LAYER WITH A TRANSITION TO SYMMETRIC INSTABILITY BY EARLY
SATURDAY. SOUNDINGS IN THE PRECIPITATION AREA INDICATE EFFICIENT
SNOW PRODUCTION AND SNOW TO LIQUID RATIOS OF 13-17 TO 1 ARE
REASONABLE. A LOOK AT THE 295K LEVEL SHOWS THE MOST FAVORABLE
MOISTURE...LIFT AND VERTICAL TEMPERATURE PROFILES WILL BE OVER
NORTHERN NEBRASKA.


.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 311 AM CST FRI FEB 28 2014

SNOW IS STILL EXPECTED SATURDAY ACROSS NORTHERN NEBRASKA...WITH
LIKELY CHANCES FARTHER SOUTH AS WELL. BOTH THE GFS AND ECMWF MODELS
HAVE A 135 KT JET SEGMENT CROSSING SOUTH DAKOTA DURING THE
DAY...WITH OUR AREA LOCATED IN THE FAVORABLE RIGHT REAR QUADRANT.
ISENTROPIC LIFT AND DECENT MOISTURE TRANSPORT IS WELL UNDERWAY AT
12Z SATURDAY MORNING...WITH A DECENT FRONTOGENESIS /FGEN/ DRIVEN
BAND OF SNOW EXPECTED TO MATERIALIZE. DECENT LIFT THROUGH A FAIRLY
DEEP DENDRITIC GROWTH ZONE...ALONG WITH COLD ARCTIC AIR IN
PLACE...WILL PROMOTE HIGH LIQUID TO SNOW RATIOS...PROBABLY ON THE
ORDER OF AROUND 19:1 OR SO. THE ECMWF CONTINUES TO BE THE FARTHEST
NORTH...WITH THE SNOW BAND CENTERING ALONG OR NEAR THE NEB/SD
BORDER. THE NAM AND GFS ARE FOCUSED A BIT SOUTH ACROSS NORTH CENTRAL
NEBRASKA. THINKING RIGHT NOW IS THAT THE AREA ALONG AND NORTH OF HWY
20 WILL RECEIVE THE HEAVIEST ACCUMULATIONS...WHERE 3 TO LOCALLY 6
INCHES ARE LIKELY BY SATURDAY EVENING WHEN THE SNOW WILL QUICKLY
TAPER OFF.

SNOW IS LIKELY FARTHER SOUTH ACROSS CENTRAL AND SOUTHWEST NEBRASKA
ALSO. PERSISTENT ISENTROPIC LIFT OCCURS THROUGH MOST OF THE DAY
SATURDAY...HOWEVER BEST FGEN IS FOCUSED ACROSS NORTHERN
NEBRASKA...SO SNOWFALL SHOULDN/T BE QUITE AS HEAVY AS IN NORTHERN
PARTS OF THE STATE. STILL...WITH THE HIGHER SNOW TO LIQUID RATIOS
EXPECTED...A GENERAL 1 TO LOCALLY 4 INCHES OF ACCUMULATION IS
POSSIBLE BY SATURDAY EVENING.

WIND AND ASSOCIATED BLOWING AND DRIFTING SNOW SHOULDN/T BE A BIG
ISSUE WITH THIS EVENT...AS THERE IS NO REAL WELL DEFINED DEEP
SURFACE LOW PRESSURE CENTER ASSOCIATED WITH THIS SYSTEM. GUIDANCE
INDICATES WINDS SHOULD GENERALLY REMAIN 15 MPH OR LESS DURING THE
DAY SATURDAY...DECREASING FURTHER SATURDAY NIGHT INTO SUNDAY.

A STRONG STORM SYSTEM CURRENTLY MOVING ONTO THE CALIFORNIA
COAST...WILL MOVE ACROSS THE AREA SUNDAY IN A MUCH WEAKER AND
DISORGANIZED STATE. NEVERTHELESS...MODELS INDICATE ANOTHER FGEN
DRIVEN BAND OF SNOW IS LIKELY TO MATERIALIZE SUNDAY MORNING AND
CONTINUE INTO THE AFTERNOON IN ASSOCIATION WITH THIS SECOND SYSTEM.
THE ECMWF SEEMS TO BE A NORTHERN OUTLIER AT THIS POINT...AND REALLY
RAMPS THE SNOW UP ACROSS SOUTHWEST INTO SOUTH CENTRAL NEBRASKA
SUNDAY MORNING. THE REST OF THE MODELS KEEP THE BULK OF THE SNOW
ACROSS NORTHERN AND NORTHEAST KANSAS. FEEL THE PREVIOUS FORECAST HAD
A GOOD HANDLE ON THIS ALREADY...AND CONTINUED THE HIGH CHANCE /50
PERCENT/ POPS ALONG AND SOUTH OF INTERSTATE 80...AND TAPERED TO THE
NORTH. THERE IS QUITE A BIT OF UNCERTAINTY FOR SUNDAY AT THIS
POINT...AS THE CENTER OF THE STRONG STORM SYSTEM REMAINS OFFSHORE
AND OUTSIDE THE UPPER AIR NETWORK. AS THE SYSTEM MOVES ONSHORE LATER
TODAY AND TONIGHT...HOPEFULLY MODELS WILL COME INTO BETTER
AGREEMENT. IF THE ECMWF WERE TO VERIFY...THEN ANOTHER 2 TO 4 INCHES
OF SNOW COULD ACCUMULATE ACROSS SOUTHWEST NEBRASKA SUNDAY. STAY
TUNED.

A WARM UP IS STILL EXPECTED BY WEDNESDAY...AS UPPER LEVEL RIDGING
DEVELOPS AHEAD OF ANOTHER WEST COAST TROUGH. HIGHS SHOULD REACH THE
40S WEDNESDAY AND POSSIBLE 50S THURSDAY...AS BREEZY SOUTHWEST WINDS
AND HIGH MARCH SUN ANGLE QUICKLY ERODE THE SNOWPACK ACROSS THE
AREA.

SOME MORE ARCTIC AIR MAY TRY TO OOZE SOUTH INTO THE REGION
FRIDAY...BUT THIS LOOKS TO BE A GLANCING BLOW AND NOT EXPECTED TO
PERSIST.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1137 PM CST THU FEB 27 2014

AN ARCTIC COLD FRONT WILL APPROACH AND PASS THROUGH WESTERN AND
NORTH CENTRAL NEBRASKA OVER THE NEXT 12 HOURS. THROUGH 15Z
FRIDAY...EXPECT ABUNDANT MID LEVEL CLOUDINESS AON 10000 FT AGL.
THE FRONT IS EXPECTED TO PASS THROUGH KVTN AT 15Z AND KLBF AT 17Z
FRIDAY. BEHIND THE FRONT...EXPECT MVFR CIGS AON 1500 FT AGL FRIDAY
AFTERNOON INTO EARLY FRIDAY EVENING. SOME LIGHT SNOW WILL BE
POSSIBLE ACROSS NORTHERN NEBRASKA...AFFECTING THE KVTN TERMINAL
FRIDAY AFTERNOON. VISBYS MAY DROP AS LOW AS 2SM IN ANY AREAS OF
LIGHT SNOW. SNOW IS EXPECTED TO END OVER NORTHERN NEBRASKA FRIDAY
EVENING...BUT WILL RETURN ON SATURDAY MORNING.

&&

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

$$

SYNOPSIS...SPRINGER
SHORT TERM...SPRINGER
LONG TERM...TAYLOR
AVIATION...CLB