Thursday, February 5, 2004


THU 2/5 EVENING UPDATE: “LUCK, BE A LADY TONIIIIGHT… LUCK, BE A LADY TONIIIIGHT. LUCK, IF YOU’VE EVER BEEN A LADY TO BEGIN WITH, LUCK BE A LADY TONIIIIIGHT.”

- Marlon Brando in Guys and Dolls, the original movie version

For all you in the Baltimore or Philly areas hoping for no school tomorrow... I would just caution you to be prepared for class, and maybe, just maybe, luck WILL be a lady tonight. Overall, the next 24-36 hours will be such an interesting and complex winter weather event, it will leave no doubt in your mind as to why a meteorologist's job can be so exciting and frustrating at the same time. This storm is probably going to be in the top five most challenging storms of the past ten years. But that's what makes it fun!

Here's our status as observed in the atmosphere at 9:00 PM Thursday:
- Snow has been falling UP ABOVE the DC-Baltimore Metro area now for hours. But upper levels continue to remain dry, so the snow is evaporating before it reaches the ground.
- Sleet and freezing rain at Reagan Nat'l Airport in DC, temp 31, dewpoint 21.
- Flurries at Baltimore Inner Harbor, temp 33, dewpoint 20
- Overcast at Philadelphia Internat'l Airport, temp 33, dewpoint 19.

What this tells us is that although snow is falling above you right now, the atmosphere remains very dry as evidenced by pressure readings averaging 30.50 inches, which is essentially a strong high pressure wedge parked over the Mid-Atlantic area. The storm is making inroads though. The rain/ice/snow line is beginning to cross the western MD mountains and nosing into SW PA. Although the snowpack did not melt as quickly as anticipated, persistent cloud cover for most of today was able to act as an insulator and kept the temperature up instead of letting it drop rapidly once night fell. So now we wait for the other shoe to drop as I will keep my hourly precip projections the same as shown below.


SO WHAT IS THE BOTTOM LINE WITH THIS STORM?


Western Maryland: A Winter Storm Warning is posted from Carroll County on west. Those areas will seen several inches of snow and then possibly up to .50" of ice before late day change to rain. Then the rain will be heavy and this will cause major flooding since the ground is frozen, and the rivers are ice-covered.

Baltimore Metro: A Winter Weather Advisory AND a Flood Watch means mixed precip as outlined below changes to all rain with 1-2 inches of heavy rain Friday afternoon and early evening. This is going to be quite an amazing event, as you will see everything from snow in the morning to torrential rain and possibly even a brief clap of thunder by afternoon. Small stream and river flooding is possible in low-lying areas as the rain will runoff the snowcover and ice-covered rivers, exaggerating the flood threat downstream. More specifically...in Baltimore County, from Towson on north to Hereford will see light snow and sleet to start late tonight, (around midnight) Computer models project a 6 hour freezing event before a rain changeover, which will move from south to north between 6 and 10 AM. That means by the time the call is made for a 2-hour delay, at 5 AM, it will be sleet and freezing rain in the city, but starting to changeover to rain by 7 AM. The rain/snow changeover will move N and W, reaching Towson by 8 AM and into the Herefore Zone by 9 or 10.

Central PA: See discussion below for more details. A Winter Storm Warning continues for all of Western PA from border to border. Snow amounts will not be great... maybe 4 inches max, but the ice threat is considerable as you will see a changeover to sleet and freezing rain early on Friday, continuing for 6 hours or more. Ice accumulations may approach 1/2 of an inch.

Philadelphia Area: Snow and sleet changing to freezing rain from the city N and W by mid morning Friday. Significant icing before an eventual changeover to rain by noon. Ice amounts could reach .25" or more in the NW suburbs. The rain to follow will be much like Baltimore's forecast... torrential for a period of time, with extremely rapid runoff due to frozen surfaces and ice-covered streams. Downstream flooding will be a major problem due to this upstream runoff situation.

Final Friday 2/5 Precip Summary for Baltimore (revised 10 PM)

BY THIS TIME... THIS WILL HAPPEN
10 PM - A passing flurry south, light snow north.
12 AM - Scattered light snow showers north, light sleet and freezing rain south.
2 AM – Sleet and freezing rain south, light snow and sleet mixed north
4 AM – Freezing rain changes to a rain/freezing rain mix in Metro area...moving from SE to NW.
6 AM – In the city...freezing rain has changed to rain.
8 AM – In the north, freezing rain turns to all rain.. first Towson, then Hereford
10 PM – Rain for everyone...becoming heavy for most of the afternoon, exceeding 1" in most areas.
7 PM - Rain may mix with snow from west to east for a short time before ending

WHAT ABOUT SCHOOL ON FRIDAY?

Baltimore Area
Frederick, Carroll and everyone else on west: Closed
Harford, Cecil, Baltimore Counties: A 2-hour delay at 5:00 AM.... then they'll re-evaluate at 6:30 AM.
Baltimore City, Anne Arundel and Howard Counties: 2 hour delay ONLY.

Pennsylvania
Most PHL area and ALL Central PA schools will be closed, maybe even Penn State again.

AND THEN...there is still a possibility the remnants of this storm will morph into a nor'easter on Saturday, leaving some snow in the I-95 cities when it is all over Saturday night.

WHEN'S THE NEXT BIG STORM...something is brewing for the middle and latter part of next week, a Tuesday-Wednesday night event. Will it be a repeat of the blizzard? Tune in later tomorrow for more details on "the rest of the story."

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