Browse Tag

8

Winter Storm Threat: February 8-10 (Only/Final Call)

This storm has a complicated setup. You have multiple surface lows within a broader upper-level trough, marginal surface temperatures, and large discrepancies in QPF placement between the models.

Temperatures along and east of I-95 are the most uncertain, which are expected to be in the low-to-mid 30s through most of the event. Areas north and west of I-95 will start above freezing, and will cool to at or below freezing depending on how strong the snowfall rates are tonight.

Snowfall rates will be one of the most important factors in determining which areas see 4-8 inches, and which areas get 1-4 inches. The best rates are likely to be along the Maryland/Pennsylvania border into southern New Jersey.

20160208-09_MAsnow_final

The intensity of the initial coastal low, the secondary coastal low development, the strength of the low over the Great Lakes, and the timing of the strengthening and weakening of these lows are wreaking havoc on the QPF output on the various models.

I tried my best to offer a realistic compromise between the differences in QPF, while also accounting for the surface temperature and snowfall rate issues. I could definitely see a tighter gradient between accumulation amounts than what I have on the map.

Winter Storm Threat: Dec 8-9 (Final Call)

Not much difference from yesterday’s forecast, with the 1-2″ contour extending further south around DC/MD and a bit further north in central PA. Cut back totals in the westernmost areas in WV and OH. Areas west of I-95 remain at risk for a likely amount of 0.1″+ of freezing rain after the snow falls, with some areas (mostly around I-81) getting into the 0.25-0.5″+ range.

Winter Storm Threat: Dec 8-9 (Initial Call)

So I’m going to just ignore tonight’s snow in the northern areas in order to focus on the Sunday event, which is quite challenging with a strong CAD signal from a 1036+ mb High over PA as the precipitation starts to move in from the south and west. I expect most areas to start off as snow or a snow/sleet mix before changing over to sleet/freezing rain and eventually just rain. There is some potential for significant impacts west of I-95 on Sunday if the sleet and freezing rain persist for awhile, but most/all of the region is expected to be just rain by Monday morning rush hour. The highest freezing rain totals are expected to be around I-81, but even areas just west of I-95 could end up with at least a tenth of an inch of freezing rain. There is still some question as to how much cold air gets locked in east of the mountains and how much QPF overruns the cold air before above freezing mid-levels bring in the sleet and freezing rain.

There’s still plenty of uncertainty and room for change, so stay tuned for updates here and on Twitter! My second (final) forecast will be up tomorrow morning.

Winter Storm Threat: Feb 7-8 (Initial Call)

Just going to start off by saying that forecast confidence is lower than normal. Miller B type storm will form up late tomorrow into Friday and will initially cause mixing/temp issues across the more southern areas. As the coastal intensifies, banding on the back edge of the system could bring locally higher totals from central PA to NJ, NY and maybe even down into northeast MD and northern DE. There’s plenty of risk in either direction, especially across central PA into NJ and NYC/LI.

I didn’t try too hard to figure out contouring based on strict temperature and boundary layer issue areas since there is not enough certainty to really go into that much detail yet. That’s a job that is best saved for tomorrow’s update.

Winter Storm Threat: Nov 7-8 (final call)

Made some changes to bring things a bit further east in general. I took out the 4-8 inch contour due to uncertainties in the forecast, but I do think there will be localized 4-8″ totals in eastern PA and western NJ. Confidence in the forecast is normal to slightly below normal.

Winter Storm Threat: Nov 7-8 (initial call)

Here we go with another early start to winter… but early start for who, exactly?

Well, the mountains already got a shock to the system last week as Sandy dumped as much as three feet or more of snow across West Virginia. This time around, it looks like the coastal areas will cash in more as those out west are left to deal with whatever remains of what they got last week. The latest model runs have (thankfully) converged on a somewhat reasonable solution for mid-week’s snow.

Despite the recent convergence, forecast confidence is still lower than normal as small shifts in the storm track could potentially lead to big shifts in the snow zone.

Fredericksburg, VA storm damage

Jason and I originally intended today’s chase to be more local to our homes in Montgomery County, MD, but as storms kept popping up to our south we kept dropping south with them. We initially crossed over into Virginia near Leesburg as a promising storm was moving into the area to our west. As that storm diminished, new storm after new storm would develop nearby and we went after them, but each storm pulsed out just as we approached the main core. Our goal for the day was getting into a hail core, but we only managed to get a couple of rounds of pea-sized hail. Eventually we ended up in the Fredericksburg, VA area and intercepted the storm that passed through there. After the main core diminished, I saw a tweet reporting damage in the Fredericksburg area and we went to investigate it.

Here is a video and a couple of pictures of the storm damage just southwest of Fredericksburg along US 1… I might get some more pictures and video processed later, but most of it has already been covered.

UPDATE:

The NWS at LWX have completed their survey and concluded that a microburst with winds of 80 mph hit the area.

000
NWUS51 KLWX 092131
LSRLWX

PRELIMINARY LOCAL STORM REPORT…CORRECTED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
530 PM EDT MON JUL 09 2012

..TIME… …EVENT… …CITY LOCATION… …LAT.LON…
..DATE… ….MAG…. ..COUNTY LOCATION..ST.. …SOURCE….
..REMARKS..

0520 PM TSTM WND DMG 3 S FREDERICKSBURG 38.26N 77.49W
07/08/2012 SPOTSYLVANIA VA NWS STORM SURVEY

*** 7 INJ *** A MICROBURST WITH 80 MPH WESTERLY WINDS
TORE THROUGH AN AREA 3 MILES SOUTH OF FREDERICKSBURG. ON
FLEMING ST BETWEEN LAFAYETTE BLVD AND ROUTE 1… A ROOF
WAS TORN OFF A GYM AND THE WALL COLLAPSED. THERE WERE 7
INJURIES IN THE GYM. THE ROOF WAS THROWN ONTO A HOME
NEXT DOOR. A FEW OTHER BUILDINGS IN THE INDUSTRIAL AREA
HAD ROOFING DAMAGE. THE INTENSE BURST OF WIND BLEW INTO
A RESIDENTAL AREA WHERE DOZENS OF TREES WERE SNAPPED OR
UPROOTED. MANY HOMES IN THE SUBDIVISION WERE DAMAGED BY
FALLING TREES.

&&

CORRECTED EVENT TIME…INJURIES…REMARKS…SOURCE

EVENT NUMBER LWX1200867

$$

STRONG

Just going to log some external links at the bottom here…

Sites that have used my media:

Alex Liggitt’s WJLA ABC 7 Blog
WeatherNation (shared on Facebook, Twitter)
Accuweather

Thank you everyone for all of the re-tweets and mentions on Twitter and Facebook!