Area Forecast Discussion
Issued by NWS Pocatello, ID

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FXUS65 KPIH 282001

Area Forecast Discussion
National Weather Service Pocatello ID
201 PM MDT TUE JUN 28 2016

.SHORT TERM...Tonight through Thursday night. A line of weak
convection has developed from the middle of the Arco Desert
stretching east toward Jackson WY. Reflectivities remain weak so
do not expect much rain to reach ground. Have already stretched
meager pops west toward the I-15 corridor for the
afternoon/evening. Models including hi-res HRRR and RAP continue
to struggle with placement of convection through the evening, with
best guesses highlighting areas along divide. With current
convection in mind believe that models are placing focus area too
far north, especially considering current trajectories
extrapolated from wv sat imagery motion and drier air mass
advecting through central mtns at this time. Regardless have kept
very low mention of pops these areas. Difficulty in pinpointing
areas of convection continues into Wednesday. Moisture surging
north through southern NV/UT may be able to reach southern
highlands by tomorrow. GFS and NAM both continue to increase mid
level moisture levels that area compared to remainder of SE Idaho
Wednesday and Thursday. However they both also maintain broad
area of mid level instability spreading further north across
central mountains and along divide. Therefore cannot rule out
isolated thunderstorms elsewhere. Higher terrain should be focus
point for initiation and have kept Snake Plain areas drier.

.LONG TERM...Friday through Tuesday. GFS continuing trend to
weaken upper ridge through the holiday weekend and early next
week. Southwest flow with some mid level moisture still in place
for Friday and Saturday and have left mainly isolated
thunderstorms most areas both afternoon and evening. Shortwave
drives through the northern tier states Saturday night into
Sunday per GFS. EC a little bit slower and more amplified. In both
cases however, surface gradient both Sunday and Monday weaker than
in previous runs. Thus have backed off slightly on wind forecast
along with guidance trends. Cooling trend also not as pronounced
so have trended temps for the 4th slightly higher. DMH


.AVIATION...Weak returns so far out of the ACCAS clouds this
morning, and models continue to keep convective activity away from
the terminals. There is a chance that KIDA and KPIH will see outflow
winds as the storms develop over the Eastern Highlands this
afternoon/evening, but not enough certainty as to when/where storms
will develop. Hinsberger


.FIRE WEATHER...Isolated dry thunderstorms should continue through
the early evening hours. Locally gusty outflow winds are possible.
Afternoon thunderstorms will increase in coverage over the next
couple days as monsoon moisture makes its way into the area. By
Thursday we should see scattered thunderstorm coverage across the
area with little to no precipitation. Min RH values will start off
in the low to mid teens and gradually increase through the weekend
as monsoonal moisture becomes better established. Trajectory of
upper shortwave has shifted further to the north Sunday and beyond
meaning less wind and less chances for thunder. Models though are
still lacking consistency just yet, so made only minor changes to
extended periods. Hinsberger


.PIH Watches/Warnings/Advisories...

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