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fxus63 kgid 212359 
afdgid 


Area forecast discussion 
National Weather Service Hastings NE 
559 PM CST Sat Nov 21 2009 


Aviation...00z kgri taf. Complex aviation forecast through at 
least the next 24hrs. Low clouds have pretty much left the area 
but will likely return once again after midnight. Low level relative humidity 
fields remain high throughout the taf valid period...but models 
differ on ceiling categories. Believe that IFR conditions continue 
to look likely towards early morning along with some areas of fog. 
Conditions will then improve by middle to late morning with low 
stratus deck and fog lifting some...perhaps into the MVFR range. 


&& 


Previous discussion... /issued 306 PM CST Sat Nov 21 2009/ 


Short term...tonight through 12z Monday. Question for this forecast 
period is temperatures and weather. Clouds hanging in there this 
afternoon and expect to see them break up some at sunset...but with 
good south flow and dew points in the middle to upper 40s continuing 
to stream north...expect clouds to return by 22/06z. With cloud 
cover and moist airmass...overnight lows should not drop off too 
far. Guidance has lows in the 30s most areas. Will opt for readings 
in the upper 30s west to lower 40s east. Would also expect fog to 
develop across the area along with some patchy drizzle. 


Clouds and fog/drizzle will be slow to dissipate on Monday and will 
expect a mostly cloudy day. This will impact high temperatures given 
that lows will be warmer than the past few days...should see maximum 
temperatures around 50 most areas. Model soundings do start to dry things 
out a little in the afternoon so any precipitation should be over by 
mid-day. 


Weak surface boundary comes through Sunday night and will help to 
dry things down just a bit and allow temperatures to fall into the 30s. 
With rather light winds...even with some drying...will see some 
patchy fog around. 


Long term...12z Monday through Saturday. Main forecast concerns 
will be chance for precipitation Monday through Tuesday night and 
temperatures. 


An upper level low moves through the plains Monday through Tuesday 
night. Models have slightly different timing and location of the low 
as it moves through the area...but basically the low moves out of 
the northern rockies early Monday and drifts through South Dakota or 
Nebraska Monday night to around Iowa by Tuesday evening...depending 
on the model. Will trend toward the 12z European model (ecmwf) but will make a few 
modifications to it. 


As the upper low moves out of The Rockies...a cold front will move 
through the forecast area Monday morning. Along the cold front there 
will be a chance for some light rain for Monday. In the morning the 
best chance will be further north but should spread across the area 
as the upper low slides in. Monday night the cooler air is pulled 
into the area as the low moves through. Models are divided on how 
much cold air gets into the area...but if the low is further south 
as the European model (ecmwf)...then it should be cold enough. Expect that the rain 
will mix with then change to snow early in the evening. In the east 
it may stay a mix of rain and snow since the colder air will be in 
the west. On Tuesday the low starts to move to the east but expect 
that there will be some wrap around precipitation with this. The 
cooler air lingers in the area and much of the area will have snow 
especially in the morning but as temperatures warm up in the 
afternoon the snow may mix with some rain especially in the south. A 
little of the wrap around precipitation lingers Tuesday night in the 
northeast...but it should be coming to an end. 


The remainder of the week should be dry as a short wave ridge builds 
into the area. As the upper low moves toward the Great Lakes a short 
wave spins around the low into the eastern part of the forecast 
area. There may be a few more clouds but temperatures at 850mb also 
cool off a little so do not expect a Big Warm up for Wednesday. As 
the ridge builds into the area on Thursday temperatures start to 
rebound...but Thursday night the warm up is taking shape with warm 
advection and temperatures at 850 mb warming about 4 to 6 degrees c 
in 12 hours. The upper ridge moves to the east Saturday and the warm 
advection decreases. So temperatures will be cooler but still be 
around average. 


&& 


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


$$