Winter Storm Watch 3, NWS North Platte, NE

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NORTH PLATTE NE
255 AM CST THU MAR 1 2007

.DISCUSSION...
H2O/PROFILERS HAS SHOWN A MID LEVEL SYSTEM ADVANCING ACROSS CENTRAL
EASTERN CWA IN THE LEADING EDGE OF LARGER WESTERN TROF. FAIRLY
STRONG DYNAMICS IN FAVORED DENTRITIC LAYER PRODUCED SNOW AMOUNTS OF
UP TO AN INCH FROM LBF UP TO ONL AREA BUT ALL THIS IS MOVING OFF TO
THE NORTHEAST AND THERE SHOULD BE A LULL IN THE PCPN TODAY. GOES DPI
SHOWING MUCH DRIER AIR FILTERING IN BEHIND THIS FIRST SYSTEM WITH
WCB STILL PUMPING MOISTURE OUT OF GULF INTO LOWER MO VALLEY. THIS
MOISTURE INTERACTING WITH STRONG LIFT FROM JET DYNAMICS AND
CYCLOGENESIS AND PRODUCING GOOD LINE OF TSRA FROM NE KS INTO ILL.
SFC LOW HAS PROGRESSED FROM SC KS TO NEAR MCI ATTM AND IS DEEPENING.
THIS TREND WILL CONTINUE AS UPPER SYSTEM CLOSES OFF OVER IA AND
OCCLUSION OF SFC LOW BEGINS TO PUSH TROWAL BACK INTO S.MN/E SD WHERE
HVY PCPN EXPECTED TODAY. MOISTURE FROM SYSTEM LOOKS TO WRAP AROUND
INTO NE ZONES BY LATE TONIGHT AND CONTINUE INTO TOMORROW. STRENGTH
OF SYSTEM WITH SFC LOW DEEPENING TO 980MB AND 1030 SFC HIGH BUILDING
INTO NW HIGH PLAINS WILL LEAD TO STRONG WINDS ACROSS MUCH OF CWA
BEGINNING TONIGHT AND LASTING INTO FRIDAY EVENING. THOUGH WE WILL
GET A SNEAK PREVIEW TODAY AS TIGHTENING PRESS GRAD ON BACK SIDE OF
DEEPENING LOW AND CAA ON BACK SIDE LEADS TO WIND ADV CRITERIA WINDS
TODAY...WINDS ON FRIDAY WILL BE UP NEAR THOSE SEEN DURING LAST WEEKS
BLIZZARD. ONLY THING LACKING ATTM SEEMS TO BE THE HEAVIER SNOWFALL
PRODUCTION NEEDED TO BRING VSBYS DOWN BELOW 1/4 MILE...THIS FEATURE
SEEMS TO BE JUST NORTHEAST OF CWA. HOWEVER AS ALSO SEEN LAST WEEK
MODELS WERE TO FAR EAST AND AS SUCH HAVE DECIDED TO ISSUE WINTER
STORM WATCH FOR NORTHEAST CWA BACK INTO EASTERN CHERRY. BEST CASE
WOULD BE S.BS ADV WITH VSBYS 1/2 MILE OR BETTER...WORST WOULD BE FOR
HEAVIER SNOW BAND TO MOVE INTO AREAS PROBABLY EAST OF HWY 183 AND
BRING WHITEOUT/BLIZZARD CONDITIONS AS WINDS WILL NOT BE ISSUE. ATTM
EXPECT SNOW AMOUNTS IN THE 1-3 INCH RANGE WITH AROUND 20 TO 1 RATIOS
WITH COLDER AIR MOVING IN BEHIND SFC LOW. HOWEVER THIS MAY BE HIGHER
IN FAR NORTHEAST CORNER. X-SECTIONS DO SHOW FAVORABLE THETA-E SFC
COMPARED TO MOMEMTUM LINE ALONG WITH SLIGHTLY NEG EPV VALUES...BUT
MUCH OF THIS IS JUST OUTSIDE THE FAVORABLE DENDRITIC LAYER SO
CONFIDENCE ALSO NOT REALLY HIGH FOR BANDED TYPE HEAVY SNOW...THOUGH
OMEGA IS PRESENT IN THIS FAVORED LAYER. SECONDARY ASPECT TO SYSTEM
WILL CONTINUE TO BE WINDS IN FAVORED AREAS OF WESTERN CWA. GUIDANCE
ALL POINTING TO HIGH WIND EVENT WITH BUFKIT MOMENTUM XFER NUMBERS
QUITE IMPRESSIVE AS WELL HAVE PLACED HIGH WIND WATCH IN FOR AREAS
MAINLY ALONG AND WEST OF HIGHWAY 61. NEW GFS RUN SHOWING ANOTHER
BACK DOOR FRONT WHICH MAY AFFECT TEMPS ON MONDAY...THIS BEING MAIN
FCST CHALLENGE ONCE THIS SYSTEM IS EJECTED BY AMPLIFYING RIDGE ON
SUNDAY.

&&

.AVIATION...
IFR CONDITIONS TO PERSIST ALONG AND NORTH OF A LINE FROM KVTN TO
KBBW THROUGH MID MORNING GRADUALLY IMPROVING TO MVFR. SUSTAINED
WINDS INCREASING TO 25 TO 3O KTS WITH GUSTS TO AROUND 40KT OVER THE
SAME AREA THROUGH THE AFTERNOON. IFR CONDITIONS OVER THE REMAINDER
OF WESTERN AND NORTH CENTRAL NEBRASKA WITH MVFR CONDITIONS
DEVELOPING WEST AFTER 6Z FRIDAY AND IFR REDEVELOPING OVER NORTH
CENTRAL NORTH OF KVTN-KBBW AFTER 6Z FRIDAY.

&&

.LBF WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING FOR
NEZ004-022-023-035-056>058-069-094.

WIND ADVISORY FROM 10 AM THIS MORNING TO 6 PM CST THIS AFTERNOON
FOR NEZ007-010-028-029.

WINTER STORM WATCH FROM FRIDAY MORNING THROUGH FRIDAY EVENING
FOR NEZ005>010-026>029.

&&

13

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE NORTH PLATTE NE
329 PM CST WED FEB 28 2007

NEZ004>010-022>029-035>038-056>059-069>071-094-010730-
SHERIDAN-EASTERN CHERRY-KEYA PAHA-BOYD-BROWN-ROCK-HOLT-GARDEN-
GRANT-HOOKER-THOMAS-BLAINE-LOUP-GARFIELD-WHEELER-ARTHUR-MCPHERSON-
LOGAN-CUSTER-DEUEL-KEITH-PERKINS-LINCOLN-CHASE-HAYES-FRONTIER-
WESTERN CHERRY-
329 PM CST WED FEB 28 2007 /229 PM MST WED FEB 28 2007/

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF WESTERN AND
NORTH CENTRAL NEBRASKA.

.DAY ONE...TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

THURSDAY STRONG GUSTY NORTHWEST WINDS ARE LIKELY FOR PORTIONS OF
NORTH CENTRAL NEBRASKA AS THE AREA OF LOW PRESSURE DEEPENS AND
LIFTS NORTHEAST ACROSS IOWA. THE STRONG NORTHWEST WINDS WILL
IMPACT AREAS EAST OF HIGHWAY 83 FROM VALENTINE TO NORTH PLATTE.

THEN AS WE APPROACH THE WEEKEND ANOTHER STORM SYSTEM MAY BE IN THE
MAKING AS THIS SAME SYSTEM LIFTS NORTHEAST FRIDAY TO ACROSS THE
NORTHWEST MIDWEST THEN DRAGS A REINFORCING SHOT OF COLDER AIR
SOUTH FRIDAY AFTERNOON WITH WINDS TO STRENGTHEN AS THE COLD FRONT
SLIPS SOUTHEAST IN THE AFTERNOON. THEN FRIDAY NIGHT INTO SATURDAY
MORNING...THE COMBINATION OF STRONG WINDS AND SNOWFALL MAY CREATE
BLIZZARD LIKE CONDITIONS FOR PORTIONS OF NORTH CENTRAL NEBRASKA IN
AREAS NORTHEAST OF A LINE FROM VALENTINE TO TAYLOR.

THE FINAL STORM TRACK AND SYSTEM STRENGTH IS UNCERTAIN AT THIS
TIME WITH LATER STATEMENTS TO REDEFINE WIND AND SNOW POTENTIALS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED THROUGH TONIGHT.

&&

THIS PRODUCT IS NOW AVAILABLE...ALONG WITH OTHER WEATHER...
HYDROLOGICAL AND CLIMATOLOGICAL INFORMATION...AT
HTTP://WWW.WEATHER.GOV/NORTHPLATTE (ALL LOWERCASE)

WFO LBF