769 
FXUS65 KPIH 240830
AFDPIH

Area Forecast Discussion
National Weather Service Pocatello ID
230 AM MDT Tue Mar 24 2020

.SHORT TERM...Today through Thursday night. Early morning satellite 
imagery was showing a low pressure trough sinking south along the NW 
coast while the regional radar depiction was showing scattered 
showers lifting ENE across SRN Idaho ahead of the advancing system. 
Numerical models show a lull in the precipitation activity as we 
approach daybreak but then ramp it back up this afternoon favoring 
the higher terrain as SE Idaho falls under an increasingly moist and 
unstable SW flow aloft as the low drifts further south along the 
coast. Once again, the models are highlighting breezy conditions 
throughout the Snake River Plain this afternoon and thunderstorm 
activity across the SE mountains as it falls under the left-front 
exit region of the upper jet. Also, the models are showing a fairly 
enhanced area of precipitation developing along the main baroclinic 
band stretching across NE Utah tonight. Thus we will continue the 
Winter Weather Advisory for the Idaho portion of the NRN Wasatch 
through Wednesday morning. By Wednesday afternoon the upper trough 
begins to drift inland across the NW states with ongoing convective 
showers expected to continue across the region. The main dynamical 
forcing shifts further SE across Utah and so I was not as bullish on 
adding a mention of thunderstorms to the forecast although we really 
can't rule out the possibility of a strike or two under the trough. 
The trough continues to progress slowly through the region and fill 
Thursday. The GFS was a little more bullish on the idea of diurnal 
convection favoring the mountain areas whereas the NAM was 
noticeably drier. I gave the GFS the nod as we continue to have 
plenty of residual moisture and at least marginally unstable 
conditions to support isolated to scattered showers...especially if 
we can manage to get some sunshine early in the day. By Thursday 
night, the trough axis shifts SE of the region with relatively drier 
conditions working into the region from the NW as a result. 
Temperatures continue to drift lower Wednesday and Thursday.


.LONG TERM...Friday through next Tuesday. East Idaho in a relative 
break Friday between departing trough to the south and next incoming 
Pacific low dropping along the coast. Weak high pressure expected to 
bring drier conditions and the beginning of a warming trend. Next 
low brings west/southwest flow for the weekend. ECMWF pushes trough 
directly east into the northern Plains while GFS and ensembles 
appear to be trying to develop Pacific low similar to recent 
systems. Either way, Sunday should be the next chance at 
precipitation most areas. GFS hints at a little bit of instability 
for Sunday, but not enough confidence to introduce thunder this far 
out, though blended toward GFS guidance for increased wind 
potential. For Monday and beyond, models diverge significantly, so 
stayed with blended guidance for remainder of the extended. DMH
&&

.AVIATION...Cold front passing through early this morning keeping 
showers and gusty winds across the region, continuing through the 
day. Ceilings expected to remain VFR/MVFR though heavier showers 
could temporarily lower to IFR. KDIJ/KSUN most likely to see the 
lower ceilings, as well as mix toward SN. Would also not be out of 
the question to see a lightning strike or two but confidence not 
quite high enough to mention more than VCSH all terminals. 
Convection should be mainly diurnally influenced so expected a 
decrease in precipitation after sunset and overnight. DMH
&&

.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory continues through 6 AM MDT Wednesday for 
IDZ060.
&&

$$