128 
fxus63 kgid 072039 
afdgid 


Area forecast discussion 
National Weather Service Hastings NE 
239 PM CST Wednesday Jan 7 2009 


Short term...for tonight through 12z Friday. 


Latest water vapor imagery from this afternoon displays a deep 
phased upper trough stretching from the Hudson Bay region into the 
southeast Continental U.S.. upstream from this trough a broad upper ridge is 
in place along the West Coast which is leaving the plains under a 
fast northwest flow regime. Past morning upper air data reveals this 
upper flow regime as a 150-160kt upper jet streak stretching from 
the southwestern British Columbia coast into the Central High 
plains. The indirect circulation associated with the exit region of 
this jet streak has provided enough lift to produce some narrow 
bands of light precipitation across the region although a dry lower 
5 to 8 kft has kept this in the form of sprinkles or flurries. 
Regional surface observation show a weak warm front over the High Plains 
with temperatures in the 50s seen west of the boundary. 


The aforementioned upper trough is prognosticated to move near the East 
Coast tonight which will also shift the upper jet streak through the 
region while the ridge along the West Coast builds into the 
intermountain west. Under this setup...the warm front over the High 
Plains will move very little through the night with some weak 
isentropic lift around the 295k Theta layer continuing to produce 
low to middle cloud cover on the cool side of the boundary. This lift 
along with the indirect circulation associated with the exit region 
of the jet streak will enhance a narrow band of frontogenesis in the 
700-600mb layer across the northeastern half of the County Warning Area into the 
early evening hours. Although the lower 5 to 8 kft will remain very 
dry...the models are showing the dendritic layer staying moist 
through the early evening hours. Given this setup...appears 
measurable precipitation looks unlikely but will keep a mention of 
snow flurries north of a Hebron to Kearney line. Otherwise...cloud 
cover will begin to diminish across the western third of the County Warning Area 
tonight as subsidence begins to take hold of this area via the right 
front quadrant of the jet. 


As the area heads into Thursday to Thursday night...the upper flow 
pattern will turn more zonal across the region as as small but 
potent wave digs into the western Continental U.S.. in response to the 
increasing westerlies across The Rockies...the Lee trough is shown 
to close off into a weak low that will push across northern Nebraska 
Thursday afternoon to Thursday night. This will drag the warm front 
slowly east across the region with winds expected to flip to the 
west to southwest behind the boundary. Other than some lingering 
morning cloud cover east of Highway 281...the entire forecast area 
should see a mostly sunny sky with temperatures varying considerably 
from northeast to southwest. Will aim for highs in the lower 60s 
around Phillipsburg...to the upper 40s to around 50 in the 
Tri-Cities and the middle 40s around Silver Creek. 


Long term...12z Friday through Wednesday. Main forecast concern 
will be temperatures. 


A cold front moves through the area early on Friday. Expect there 
will be cooler temperatures behind it...but the significantly colder 
air will be moving into the area later in the afternoon. An upper 
wave will move into the area in the afternoon as well. Despite this 
wave...do not expect there to be precipitation since there is not 
much low level moisture as the front and upper level wave move 
through. A surface high pressure system moves into the area Friday 
night and clears things out. As with the past few systems...the cold 
air is short lived and warmer air moves into the area Saturday 
through Sunday. 


The next cold front moves through the area Sunday night and cools 
things down again. Once again this system appears to be mainly dry. 
Models have some spotty light quantitative precipitation forecast across the area...but nothing 
widespread for the forecast area. Northwest flow continues through 
Wednesday and the cooler air lingers a little longer. 


&& 


Aviation...for the 18z kgri taf. Scattered flurries and 
sprinkles are expected to occasionally brush the Grand Island 
terminal through this afternoon to evening as the exit region of 
an upper jet streak provides enough lift to squeeze out some light 
precipitation. Overall coverage of sprinkles or flurries is not enough to 
warrant including in the prevailing weather group through the 
afternoon to evening. Nonetheless...VFR cloud ceilings look to 
gradually lower to an MVFR ceiling around 2 to 3 kft during the 
evening. Otherwise...the system will then push east of the region 
later tonight with Thursday morning looking quiet as winds turn 
around to the south while some scattered high cloud cover streams 
over the region. 


&& 


Gid watches/warnings/advisories... 
NE...none. 
Kansas...none. 
&& 


$$