Seattle, WA2-7-11

Where is Seattle?

Satellite

http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?ir_common+/48h/3h

Satellite shows one system moving over the Seattle area this past weekend. A ridge deepens, much like last week. There is a synoptic low over the Pacific with a HUGE cold front, but the storm seems to be moving more northerly than westerly. What is causing that? The deepening ridge.

Radar

http://www.rap.ucar.edu/weather/radar/displayRad.php?icao=KATX&prod=bref1&bkgr=black&endDate=20110207&endTime=-1&duration=3

Showers are in the area today, but mostly away from Seattle. The rain seems scattered and not convective.

http://www.rap.ucar.edu/weather/surface/index.php?metarIds=KSEA&hoursStr=past+60+hours&std_trans=translated&num_metars=number&submit_metars=Retrieve

The temperature isn't varying very much. The humidity was higher earlier in the day and is still pretty high, so temperatures aren't moving around.

500 mb heights and vorticity http://www.nco.ncep.noaa.gov/pmb/nwprod/analysi

s/namer/nam/12/index_500_m_loop.shtml 700 mb heights and relative humidity

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/nam/12/index_700_m_loop.shtml

MSLP, 850mb T, and Precipitation http://www.nco.ncep.noaa.gov/pmb/nwprod/analysi

s/namer/gfs/12/index_pcp_m_loop.shtml

500 mb

There is a shortwave that develops in the standing long wave over Washington today. Note the high values of vorticity on the front edge of the ridge. It's odd to see that, but it's because of the shortwave that's moving through.

There is a cut off high over the Pacific. The strong high pressure keeps the ridge in place all week.

750 mb

The beginning of the loop shows lots up mid-lever moisture over Washington and neighboring states. That moisture moves off fairly quickly as the shortwave propagates eastward.

High pressure builds through the week and moves north, pushing most of the moisture into Canada

MSLP

Some precipitation is possible overnight and it should end between 6Z and 12Z if it happens (I'm going with a no).

As high pressure moves in, the 850mb temperature warms, so there may be some warming during the week.

MOS

GFS 45 36 5 0

NAM 46 36 10 0

THIS IS A 6Z LOW!

USL (not MOS) 43 35 11 0

My (wrong) forecast

High 46 Winds are all over the place The temperature will be a little warmer

Low 37 Overnight clouds hanging around 6Z low could be a deal breaker so may go lower

My Forecast Continued

Winds 10 Winds are going from south to north behind the

storm Winds should pick up during the day

Precip 0 It ain't gonna rain

The End

Me 46 37 10 0

NWS 46 36 8 0?

ter@hawaii.edu