Forecast Discussion: Severe Warmth and Severe Storms
We are going to make one more run at some super duper high octane warmth before the realities of March slap us in the face in a day or so. Today's weather will feature some fog north and west of the city, a run at 80 in Philadelphia, and a risk of severe weather. Oh, there's still a chance of a mix of rain and snow in a few days as well! Beware the Ides (or near Ides) of March indeed!!!
Fog is holding its own N & W of Philadelphia this morning. There's a very sharp cutoff between 1/4 mile visability and low ceiling in the suburbs north and west of the city and no cloud deck from the fog. The warm front (at least at 6 AM) looks to be wedged into the city and advancing northward.
There are three main questions with regard to today:
(1) How warm will it get?
Depends on how much sun we get. Philadelphia, with the lack of low clouds in place this morning in places, has a good shot at 80. The airport is foggy at 6 AM but Center City is clear to partly cloudy with no fog. This will be an interesting day regarding temperatures because the later the fog holds in the lower the temperatures will be. I think fog will hold in longer in the Lehigh Valley and in the Poconos. However, even Allentown has a good shot at the low 70's today.
(12 Noon Update) -- Temperatures into the low and mid 70's in South Jersey. Upper 70's looks reasonable there. 71 in Northeast Philadelphia with a bump of 5 degrees in the last hour so 75 to even upper 70's is reasonable for the Philadelphia immediate area this afternoon. Mid to upper 60's to the N & W will likely yield highs between 70 and 75.
(2) How bad will the forecasted storms get?
This depends as well on the amount of sun we get. The Storm Prediction Center has almost all of us under a Slight Risk of severe weather for today -- with the exception being the immediate shoreline and 15 miles inland. The potential exists for tornadic activity and wind -- partly due to wind shear from the strong SW surface component that we should see later today combined with low level winds which will come from the west/southwest at around 60-70 mph. This slight difference in wind direction may be enough to fire off a tornado or two. The best threat for any tornadoes will be across Southeastern PA. IF anything develops, these storms will likely fire late this afternoon and early this evening in South Central PA (after 4 PM but more likely after 6) and race ENE through the Delaware Valley, likely along the downsloping dry line in Pennsylvania.
It is possible that we see two waves of precip with this event tonight. The first wave being the thunderstorms that develop in Pennsylvania with the second wave being with the frontal boundary itself. It is possible that this may bring gusty winds down to the surface and drop another shot of rainfall as the front moves through. If the first wave of storms are stronger and more extensive in coverage the second wave could possibly weaken as it advances through the region late tonight. Temperatures tonight should stay between 50 north and 60 south and east.
(3) When will the front pass through and reality hit us in the face?
I'm thinking the front should pass through the region between 4 and 8 AM Tuesday. Temperatures will drop around 10 degrees after the frontal passage and then hold steady or bounce back a couple of degrees in the afternoon. Likely highs on Tuesday look to be before the frontal passage -- temperatures during the day should be in the 45-50 range across most of the area with a gusty west and northwest wind.
Wednesday and Thursday look to be a few degrees below normal with breezy conditions -- highs between 43 and 50 with mostly sunny conditions Wednesday and increasing clouds Thursday.
Friday's system looks to be a quick hitter -- but the track and timing of this event continue to be inconsistent. Right now, the low looks to track along I-70 in Maryland and then offshore near Ocean City, MD. IF this track holds, it may snow or be a mix of rain and snow for places inland especially over Northern DE and South Jersey with rain further south. This would keep snow chances off the board for anyone north of the PA Turnpike and 195 with a possible quick shot of snow or a mix in Philadelphia. After today's events play out, this will be the system to watch for the rest of this week with another system to follow for early NEXT week.
"Tracking The Event" will be running all day today, showing any storms that do develop.
Fog is holding its own N & W of Philadelphia this morning. There's a very sharp cutoff between 1/4 mile visability and low ceiling in the suburbs north and west of the city and no cloud deck from the fog. The warm front (at least at 6 AM) looks to be wedged into the city and advancing northward.
There are three main questions with regard to today:
(1) How warm will it get?
Depends on how much sun we get. Philadelphia, with the lack of low clouds in place this morning in places, has a good shot at 80. The airport is foggy at 6 AM but Center City is clear to partly cloudy with no fog. This will be an interesting day regarding temperatures because the later the fog holds in the lower the temperatures will be. I think fog will hold in longer in the Lehigh Valley and in the Poconos. However, even Allentown has a good shot at the low 70's today.
(12 Noon Update) -- Temperatures into the low and mid 70's in South Jersey. Upper 70's looks reasonable there. 71 in Northeast Philadelphia with a bump of 5 degrees in the last hour so 75 to even upper 70's is reasonable for the Philadelphia immediate area this afternoon. Mid to upper 60's to the N & W will likely yield highs between 70 and 75.
(2) How bad will the forecasted storms get?
This depends as well on the amount of sun we get. The Storm Prediction Center has almost all of us under a Slight Risk of severe weather for today -- with the exception being the immediate shoreline and 15 miles inland. The potential exists for tornadic activity and wind -- partly due to wind shear from the strong SW surface component that we should see later today combined with low level winds which will come from the west/southwest at around 60-70 mph. This slight difference in wind direction may be enough to fire off a tornado or two. The best threat for any tornadoes will be across Southeastern PA. IF anything develops, these storms will likely fire late this afternoon and early this evening in South Central PA (after 4 PM but more likely after 6) and race ENE through the Delaware Valley, likely along the downsloping dry line in Pennsylvania.
It is possible that we see two waves of precip with this event tonight. The first wave being the thunderstorms that develop in Pennsylvania with the second wave being with the frontal boundary itself. It is possible that this may bring gusty winds down to the surface and drop another shot of rainfall as the front moves through. If the first wave of storms are stronger and more extensive in coverage the second wave could possibly weaken as it advances through the region late tonight. Temperatures tonight should stay between 50 north and 60 south and east.
(3) When will the front pass through and reality hit us in the face?
I'm thinking the front should pass through the region between 4 and 8 AM Tuesday. Temperatures will drop around 10 degrees after the frontal passage and then hold steady or bounce back a couple of degrees in the afternoon. Likely highs on Tuesday look to be before the frontal passage -- temperatures during the day should be in the 45-50 range across most of the area with a gusty west and northwest wind.
Wednesday and Thursday look to be a few degrees below normal with breezy conditions -- highs between 43 and 50 with mostly sunny conditions Wednesday and increasing clouds Thursday.
Friday's system looks to be a quick hitter -- but the track and timing of this event continue to be inconsistent. Right now, the low looks to track along I-70 in Maryland and then offshore near Ocean City, MD. IF this track holds, it may snow or be a mix of rain and snow for places inland especially over Northern DE and South Jersey with rain further south. This would keep snow chances off the board for anyone north of the PA Turnpike and 195 with a possible quick shot of snow or a mix in Philadelphia. After today's events play out, this will be the system to watch for the rest of this week with another system to follow for early NEXT week.
"Tracking The Event" will be running all day today, showing any storms that do develop.
