Weather

579 
fxus63 kgid 111931 
afdgid 


Area forecast discussion 
National Weather Service Hastings NE 
231 PM CDT Sat Oct 11 2008 


Short term...tonight through 12z Monday. Main forecast concerns 
will be temperatures tonight and precipitation chances through the 
period. 


Current radar has some showers and isolated thunderstorms across the 
area already this afternoon. Expect the coverage for these showers 
and isolated thunderstorms will continue to expand through the night 
especially in the western part of the area. Surface analysis has a 
nearly stationary front across the forecast area. This front has 
been trying to move to the east but has gained little ground in the 
past few hours. Tonight this front should move back to the west as 
an upper level wave moves in. This should keep the best chance for 
precipitation in the western part of the forecast area. The westward 
moving front will also cause some concern with temperatures. High 
temperatures this afternoon in the west have been struggling to 
reach 50 degrees. As the front moves to the west temperatures may 
reach their High Point tonight. Expect that the low could be early 
then have steady or possibly warming during the night. 


With the front to the west in the morning expect that temperatures 
will warm with strong south winds tomorrow...even with cloud cover 
and rain showers. There is enough instability around tomorrow that 
there could be some isolated thunderstorms. The better chance will 
be in the morning when the MUCAPE is around 500 j/kg. During the 
afternoon and into Sunday night the cape diminishes and even though 
there is an outside chance for thunderstorms will keep isolated 
mentioned through the night. Another upper wave moves through the 
area Sunday night and as the front moves through expect that there 
will be showers. 


Long term...Monday through Saturday. The main story is the 
progression of the longwave trough and the split closed low centers 
to cross the plains. Beginning Monday morning...the cold frontal 
boundary will be on the periphery of our southeast County Warning Area...and rain 
showers will be ongoing. The upper trough slits into two distinct 
closed low pressure systems with the northern piece lifting 
northeast into Ontario...while the southern system sits in The 
Four Corners region and doesn't lift out until Tuesday. 
Frontogenetic forcing along the boundary will provide continued 
chances for precipitation during the day on Monday...particularly in 
our southeast counties in proximity to the front. As the boundary 
shifts farther southeast during the day...drier air will begin to 
work its way southeast behind the front. There should be a fairly 
defined gradient as to how all of this sets up...precipitation vs no 
precipitation...but trying to nail this down a couple days out is still 
difficult giving the slowing trends/split systems of the models. 


The stalled frontal boundary to our southeast Monday evening will 
begin to lift north a bit Monday night as the upper low near The 
Four Corners region begins to fill and lift out across Nebraska and 
Kansas. Lift increases over the baroclinic zone and precipitation 
chances continue through Tuesday...before ending Tuesday night as 
the trough axis passes. Now where the precipitation sets up Monday night and 
Tuesday is still in question with the majority of the models 
favoring our southern zones...while the GFS suggests a fairly 
widespread swath of rainfall across our entire County Warning Area. For now have 
kept the better chances south but will need to monitor trends here. 
All in all a prolonged duration of rainfall will unfold the next few 
days and significant rainfall totals are expected when all is said 
and done. Precipitable water values average an inch to an inch and 
a half across the southeast two thirds of our County Warning Area...and expect rain 
totals to average 1 to 3 inches with locally higher amounts. 


Temperatures on Monday will struggle in the Post frontal colder 
airmass...cloud cover and potential for rainfall. Have lowered 
highs closer to near 50f. Low temperatures will also be on the cold 
side both Monday night and Tuesday night with some 30s 
forecast...and will have to monitor lows for frost potential. 


Beyond the first wet and cool couple of days in the 
extended...heights rise midweek and temperatures moderate. A 
generally dry pattern sets up and temperatures return to the middle and 
upper 60s for highs with the upper ridging by the first part of next 
weekend. 


&& 


Aviation...18z taf. MVFR ceilings are expected through much of 
the period with some IFR for a time early in the period. Expect 
that the lower clouds will lift a little by middle afternoon. Some 
isolated thunderstorms are possible especially in the next few 
hours...but there is a chance there will be some isolated thunder 
around. Chances for rain continue through the period and increase 
later in the period. 


&& 


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


&& 


$$