Wednesday, February 23, 2005
Mid-day update: Snow threat continues
Steve Scolnik @ 2:20 PM
Don't put away those L.L.Bean flannel-lined jeans yet. Reports of the demise of winter were a bit premature.
Now
At mid-day, temperatures are several degrees colder than yesterday with a generally NNW breeze. Highs should be in the mid 40's and lows tonight in the upper 20's to 30. But, you didn't come here to hear that, did you?
The main event
This morning's models continue to show a low-pressure area developing over Texas, moving across the Southeast, and then off the Atlantic coast. What does that mean for DC? Let's check the Momma Nature Weather Grill recipe book:
So, what could possibly go wrong with a forecast of snow in DC tomorrow? As legions of disappointed snow fans know, plenty. In this case, the major risk to the forecast is that the low will develop as predicted and move out to sea too far south of us to give much snow. As a storm earlier showed (I think in late December), Norfolk and the Delmarva can get walloped and the DC area and even central Virginia get zilch. Right now, the best indication is that DC will be on the northern edge of the snow area, with heavier amounts through central Virginia.There will be plenty more to discuss as this evolves.
Now
At mid-day, temperatures are several degrees colder than yesterday with a generally NNW breeze. Highs should be in the mid 40's and lows tonight in the upper 20's to 30. But, you didn't come here to hear that, did you?
The main event
This morning's models continue to show a low-pressure area developing over Texas, moving across the Southeast, and then off the Atlantic coast. What does that mean for DC? Let's check the Momma Nature Weather Grill recipe book:
- Cold air: Got that, and there is a strong high-pressure ridge at upper levels over northwestern North America bringing in reinforcement if needed.
- Moisture: The southern branch of the jet stream has brought enough rain to southern California to give Los Angeles its second-wettest rainy season on record. Some of that southern-branch moisture brought heavy thunderstorms to Texas and eastward to the Southeast yesterday.
- Energy: Some of those thunderstorms in Texas were strong enough to produce grapefruit-sized hail. There is also an area of energy (technically, vorticity) in the northern branch of the jet stream moving out of the Northern Plains and forecast to move through northern Missouri tomorrow morning, then across southern Illinois and the Ohio Valley. Today's model forecast has increased the intensity of this from what was being predicted yesterday.
So, what could possibly go wrong with a forecast of snow in DC tomorrow? As legions of disappointed snow fans know, plenty. In this case, the major risk to the forecast is that the low will develop as predicted and move out to sea too far south of us to give much snow. As a storm earlier showed (I think in late December), Norfolk and the Delmarva can get walloped and the DC area and even central Virginia get zilch. Right now, the best indication is that DC will be on the northern edge of the snow area, with heavier amounts through central Virginia.
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