Area Forecast Discussion
Issued by NWS Pocatello, ID
Issued by NWS Pocatello, ID
682 FXUS65 KPIH 060903 AFDPIH Area Forecast Discussion National Weather Service Pocatello ID 303 AM MDT Mon May 6 2024 .SHORT TERM...Today and Tuesday Our next round of precipitation is pushing through the region already this morning. With it, rain and snow is expected with snow likely the most dominant precip type once again despite the fact that it is May. An upper low basically over the region will keep temperatures well below normal once again today with highs in the 40s and 50s regionwide. Early this morning however, most spots are in the 30s and with the freezing level just above the surface, expecting snow for the first part of the day. Not expecting much if any accumulations in the Snake Plain or Magic Valley with marginal surface temps although some light accumulations on elevated and grassy surfaces is certainly possible. We will see accumulations however above 5500 feet or so in the eastern highlands and Winter Weather Advisories remain in place into the first part of the day Tuesday. 3 to 6 inches of snow is expected in these areas with much higher amounts expected above pass levels. A Winter Storm Warning continues in the Bear River Range where 1 to 2 feet could fall in the next 36 hours or so. In addition to the cold and snow, winds will also be an issue today (and tomorrow) and a Wind Advisory continues for the Magic Valley, South Hills and into the Arco Desert and lower Snake River Plain. Winds in the 25-35 mph range are expected with gusts in the 40-50 mph range likely. Tuesday looks very similar as far as winds and temps are concerned. Precip however will be more showery in nature as things begin to dry out slowly as we transition back into a more seasonal, warmer, drier pattern by mid/late week. McKaughan .LONG TERM...Wed through Sun Precipiation still on track to end Wed night, with high pressure dominating the upper levels over the northern Rockies and northern Great Basin from Thu morning to the almost the end of this period. For Wed/Wed night, none of the precipitation from the departing low will amount to 0.10 in any 24 hour period. The only possibility would be enough warming and some unstable air that afternoon/evening thunderstorms would be an issue. Thu and Sun appear to be the current best likelihood days, and it is all focused on the eastern highlands, from MT border to the UT border. Just in time for Mother`s Day, a very weak shortwave breaks down the upper level ridge over the Panhandle and the very northern end of the forecast area. This may trigger some afternoon showers and thunderstorms. Another forecast challenge will be how the temperatures react to sunny days, clear nights, and the occasional thunderstorm. Wed continues very cool with a very cold start to the day and only eking out the warmest elevations to the lower 50s. Overnight lows will challenge the freezing point again for Wed night, then the clear skies of Thu allow afternoon temperatures to soar 10 to 15 deg F above the previous day, though still below climatic normals. Thu night and Fri are still the days we reach or surpass climate normals, and the warming levels off to a gradual 1 deg F per day. This is likely to do with the upper level pattern of easterly to northerly airflow; thus the extended MOS guidance is trending warmer than the NBM and other consensus guidance. Have gone the the more gradual warming trend. Breezy winds continue for portions of the forecast area Wed, then some gusty northerly wind for Thu and Fri, and thus the slower rise in temperatures. The southerly wind returns on Sat. Beyond Thu, the winds really weaken and are not seen as an issue at all. Messick && .AVIATION... MVFR conditions likely to prevail for most of the first half of the day as rain/snow push back into the region. In addition to the precip, winds will be quite windy at KBYI, KPIH, KIDA and to a lesser extent KSUN and KDIJ. Nevertheless, it should be an impact day at all terminals across eastern Idaho. Precip early will likely be in the form of snow with precip a transition to a mix or all snow in the valley terminals by early afternoon. Could see some thunderstorms as well later although chances are probably on the lower end, kept in VCTS for now. Should see a bit of a break on the precip by later in the evening but winds will remain elevated through the period and into Tuesday. && .HYDROLOGY... Flooding has dropped to minor flood stage at the Portneuf River at Pocatello potentially rising back into moderate flood stage in a few days after all the precipitation falls over the next few days. Either way, minor flooding is expected to continue here and at Topaz. Flood warnings also remain in effect for the Blackfoot River near Shelley at Wolverine Canyon with the river remaining at flood stage and also near Blackfoot where the river remains in flood stage. With more precipitation the next few days, rivers will be to be monitored closely. McKaughan && .PIH WATCHES/WARNINGS/ADVISORIES... Wind Advisory from 6 AM this morning to 8 PM MDT this evening for IDZ051-052-054>057. Winter Weather Advisory until 6 AM MDT early this morning for IDZ056-057. Winter Storm Warning until 6 AM MDT Tuesday for IDZ060. Winter Weather Advisory until 6 AM MDT Tuesday for IDZ062>066. && $$