Tuesday, January 16, 2018

Backdoor Front Here and Misc.

First - a cold, blue norther has plunged south across the Southern Plains and into the lower Mississippi Valley this morning - surface plot above is from 6:00 am CST. Webcam photo below shows I-20 at Shreveport, Louisiana. School closings galore, as well as hazardous travel conditions with novice ice-drivers spinning all directions.

Here in Tucson a backdoor portion of the Plains front is impacting our are with east winds and mild morning temperatures. The surface plot above is from the 06 UTC WRF-GFS and is valid at noon today. Temperatures will be down about 10 F relative to midday yesterday. Plot below, from same model run, shows the forecast winds for noon today with some low-level gusty east winds. As always, the east winds , along with some clouds, makes temperature forecasting here very difficult, especially for morning lows.

In the longer term, the WRF GEFS ensmbles forecast a strong, 500 mb short wave to cross the state Friday and Saturday. The attendant cold front knocks TUS temperatures way down - above T plumes from 06 UTC GEFS - late Friday (corrected) through Monday the 22nd.

The WRF-GFS forecast of precipitation through 5:00 pm (below from 00 UTC model run on 5.4 km grid) continues our dismal spell of mostly dry weather. This forecast is driven by the operational GFS, which is almost the driest member of the GEFS. The plumes for QPF show some chance for light showers as the front approaches and moves by.

No comments:

Post a Comment