Program Status for 31 January 2001 : IOP 04

Status

January 31 1100 PST	Super IOP in progress
February 1	Proposed flight 1100 PST Mission: Storm surveillance, fluxes, IMPROVE coordination. Weather briefing at 0830 (PST)

Status | Forecast Discussion | Aircraft Status | Flight Plan | Soundings Status | Special Notes

PACJET IOP4 Short Term Forecast Discussion
National Weather Service/PACJET Operations Center, Monterey, CA
2245 UTC January 31, 2001

Discussion: The highly amplified ridge now overhead the west coast will flatten over the next 24 hours as strong jet energy...extending across the eastern Pacific...approaches the Pacific Northwest. Latest model runs from 12Z this morning appear fairly well initialized...though it did look like they were a little slow with the 6 hour forecast valid at 18Z in the handling of the initial short wave now approaching 45N/140W. The main vort center that is crossing 40N/155W appears on track with current forecasts. Today's PACJET flight is sampling in this region... and hopefully will provide valuable data for the initialization of the 00Z model runs.

In any case...appears that conditions are taking shape for a significant precipitation event for the Pacific Northwest given the strength of the incoming system and ample available moisture (precipitable water values exceeding an inch as far north as 50N). Appears warm advection precip will spread down from Vancouver Island into northwest Washington by midday Thursday. Precipitation will then increase across western Washington and western Oregon Thursday night and early Friday as the cold front moves onshore. Strong southerly flow of 50 to 70 knots at 850 mbs will enhance rainfall along south and southwest facing slopes. Moist westerly onshore flow behind the front will keep moderate precipitation going across much of the Pacific Northwest through Friday. Current thinking here is that some light precipitation will make it about as far south as areas north of the Bay Area and Sacramento by late Friday as the front washes out across northern California.

ECMWF and MRF now in better agreement with a weaker system approaching the Oregon coast by late Sunday.

Rowe

Status | Forecast Discussion | Aircraft Status | Flight Plan | Soundings Status | Special Notes

Status | Forecast Discussion | Aircraft Status | Flight Plan | Soundings Status | Special Notes

Status | Forecast Discussion | Aircraft Status | Flight Plan | Soundings Status | Special Notes