Area Forecast Discussion
Issued by NWS Boise, ID
FXUS65 KBOI 281548
Area Forecast Discussion
National Weather Service Boise ID
948 AM MDT THU JUL 28 2016
.DISCUSSION...An upper level ridge anchored over the southwestern
states will keep a hot and dry west to northwest flow over the
area today. Latest guidance does suggest that max temperatures
today will be down slightly compared to yesterday. Attention will
be focused on monsoonal moisture creeping into the forecast area
as we head into the weekend. Current forecast on track.
.AVIATION...VFR. Smoke layers and MVFR visibilities KEUL through
KMUO this morning, and near Lowman ID and surrounding valleys this
afternoon/evening with obscuration. Surface winds W-NW 10-15KT 18Z-
03Z, then diminishing. Winds aloft through 10KFT MSL, NW 10-20KT.
SHORT TERM...A degree or two cooler today following yesterday`s
weak short wave trough then back up to yesterday`s temps on
Friday. We trimmed the slight chance of thunderstorms near the
Nevada border Friday afternoon as latest models have become a
little drier there. Light winds today and Friday except in the
Upper Treasure Valley and western Magic Valley where west or
northwest winds will blow 15 mph in the afternoons.
LONG TERM...Friday night through Wednesday...A trough develops
over British Columbia on Saturday, turning the upper-level flow
around to the southwest, and drawing up some moisture from Nevada.
But timing and strength of the developing trough is still somewhat
different between models, so not particularly confident in the
magnitude of the thunderstorm threat from the moisture, and have
kept just slight chances, mainly over the mountains, and mainly in
the southern and eastern parts of the forecast area. With southwest
flow, temperatures should be about 10 degrees above normal on
Saturday. Models DO agree that the trough rapidly pushes eastward on
Sunday, pushing moisture out of the area, and bringing temperatures
back down to near normal and with breezy conditions across the area.
After that models have changed rather dramatically, with another,
stronger, trough diving into Washington early in the week, and
possibly pushing across the forecast area on Tuesday night or
Wednesday. Timing is quite a bit different between the models, but
they are all much more amplified than earlier runs. This leads to
quite a bit more temperature variability, with Monday possibly well
above normal again. Then, with the trough pushing through Tuesday or
Wednesday, temperatures drop down to slightly below normal for the
first time in quite a while, and we could see fairly significant
winds on Tuesday as well. Enough model timing differences, and run-
to-run differences, that confidence is low in the details, but
trended the forecasts this direction.
PREV SHORT TERM...LC
PREV LONG TERM....TB