152 
fxus63 klbf 140842 
afdlbf 


Area forecast discussion 
National Weather Service North Platte NE 
342 am CST sun Mar 14 2010 


Discussion... 
500 mb analysis showing strong blocking ridge extending across southeast 
Canada into the northern High Plains. This is oriented more east to 
west from 24 hours ago which has allowed the upper low to move from 
middle MS valley into the Middle Atlantic States. Deep easterly flow 
between the interface of these features continuing to feed moisture 
into MO valley region with a strong feed from subtrop moisture 
according to GOES dpi tpw product. Surface analysis has shown high 
pressure strengthening and building down the plains the past 6 
hours. This aiding the isentropic lift on eastern edge of the ridge 
with water vapor/profilers indicating weak wave move westward across 
the MO valley aiding in ascent. Very light rain/snow showing up on 
mosaic/metars across eastern sdakota and these trends and new 
guidance indicates that bulk of precipitation should be east and north of County Warning Area 
and retained only small chance probability of precipitation across the northeast...with quantitative precipitation forecast 
amounts of only a few hundredths of an inch expected. Stratus 
filling in across bulk of County Warning Area by 08z with dense fog limited to 
extreme northeast County Warning Area. Sref visibility probs overestimating extent of this 
fog and confidence fog will be seen across much of County Warning Area especially 
with stratus moving in place. Most likely areas along the edge with 
would be far western County Warning Area. Looks like stratus should retreat back 
northward through the late morning/early afternoon leaving some 
sunshine in across southwest Nebraska and into some of sandhills...but 
far north does not look to be as lucky and British Columbia MOS/guidance 
reflecting this and used a blend again for temperatures with near 50 
far south to upper 30s far north...fairly similar to saturdays 
temperatures. Patchy fog and stratus should rebuild back in tonight 
with little change in airmass or pattern expected until daylight 
hours on Monday when flow will become more westerly through the 
sounding with drier air moving into the High Plains. Stratus may 
break quicker initially on Monday but low level cold air advection and increasing lapse 
rates aloft may lead to strato cumulus develop through the day and expect 
temperatures to mainly be in the middle to upper 40s. Warm up looks on track 
on Tuesday and Wednesday before next front arrives on Thursday and 
brings precipitation back to the forecast for late week into the weekend as 
northern stream becomes more active and dives into The Rockies and 
Central Plains. 


&& 


Aviation... 
widespread ceilings at or below 1500 feet above ground level will continue 
through late morning in much of western Nebraska. Instrument 
ceilings in north central Nebraska may spread as far west as 
Valentine and Broken Bow an possibly as far as Mullen...Ogallala and 
Imperial. There is also a possibility of visibility less than 3sm 
and maybe even less than 1sm. Current conditions keep the instrument 
ceiling and visibility east of an anw-bbw line. I am not real 
confident yet that those instrument conditions will reach North 
Platte...but it will need to be monitored for updates and possibly 
included in the 1130z terminal forecast issuance. With the dirty 
ridge continuing over the High Plains...the possibility of low 
ceilings and visibility may present a challenge for the forecasts 
even beyond today and tonight. 
&& 


Lbf watches/warnings/advisories...none. 


&& 


$$ 


13/Springer