Forecast Discussion: Monday, Foggy Monday
11 AM Update:
Center City was fog-free by 9 AM and temperatures are rising quickly into the mid 50's. However, places N & W of Philadelphia are still locked in with fog:
11 AM Temps:
I'm still confident that N & W will be the last to break into sun and consequently, temperatures will be kept down somewhat. Don't be surprised though to see some low 50's though in places especially near Quakertown and elsewhere. It's going to be take a while for some places to break into the sun but once they do, temperatures will bounce up a good bit.
Rest of the discussion is below!
Welcome to the land of fog. Dense fog advisories are out this AM generally west of the Delaware River for visibilities down to 0. My drive into Center City this morning featured going from mile plus to 0 visibility within the span of a few hundred feet. The worst conditions as of 6 AM are in Quakertown, which is reporting 0 vis and in Valley Forge, which is also featuring 0 visibility.
Given the light flow aloft and at the surface this morning as well as the low sun angle, I believe this fog will hang in a little longer and thus, I'm going to be conservative with high temperatures (around 48-53 for Philadelphia) for the area. If the fog lifts by mid-morning, the temperatures will be higher than that because there are few clouds aloft. However, I do think that low clouds and fog will be the rule as opposed to the exception, especially north and west of the Delaware River for most of the day.
As for our coastal storm, it will still develop but I tend to think that the best precip chances will be EAST of Philadelphia. A moisture stream is sitting offshore of the Carolinas this morning will get a mid level impulse added to it and it will fire a nice coastal low that will increase the wind for us Tuesday. Yesterday, I stated that I felt the chances of precip (read: RAIN) would be best confined to South Jersey and Delaware and I still feel that to be the case...but I would not be surprised to see some rain drift up into the I-95 corridor or even some of the suburbs. Rain amounts for South Jersey and Delaware look to be 1/4" - 1/2". With a deepening low moving to our east, NW winds will keep the temperatures down Tuesday...mainly in the low 40's with upper 30's for the Lehigh Valley. A few wet snowflakes are possible up towards NYC if enough cold air wraps into this system but I think the best chances for any snow would be over parts of SE New England (and those chances of snow are low).
Temperatures for the rest of the week should be about 5-10 degrees above normal with little in the way of precip until this weekend. Our next storm is looking to threaten in the Saturday-Sunday timeframe but there are a myriad of model solutions for the event at this point. The UK wants to develop another coastal event with the Canadian developing an inland storm system over the South Central US. The GFS develops the bomb over NE PA and shoots it up into New England. Three solutions, three different events that would play out...
The UK would be the quickest (Friday) with light rain and some backlash snow POSSIBLE at the Jersey Shore.
The GFS would be rain with the event ending as snow over the Poconos.
The CMC (Canadian) is too far out to see to be certain of precip type but we could be looking at rain if the low kept an inland track.
Given how we're still stuck in a zonal pattern, things are slow to change. Despite the super cold air up over Alaska (-55 and colder in places), it has not shown any signs of moving towards the US. The long-range models hint at cold coming down the pike towards us around 10 days but given how often they have been showing cold at the 10-14 day range, I'm not optimistic that the pattern changes much. We may see cool downs followed by brief warm ups, but that super cold, at least for now, may stay locked up to the north. If you want to blame anything, blame the jet stream for being zonal for the last seven weeks and keeping the real cold air locked up over Alaska.
Center City was fog-free by 9 AM and temperatures are rising quickly into the mid 50's. However, places N & W of Philadelphia are still locked in with fog:
11 AM Temps:
CITY SKY/WX TMP DP RH WIND PRES
SCRANTON PTSUNNY 48 43 82 W3 29.78S
MOUNT POCONO MOSUNNY 49 37 64 SW7 29.78S
ALLENTOWN FOG 42 40 92 CALM 29.82S
READING FOG 42 42 100 CALM 29.82R
LANCASTER FOG 43 42 97 CALM 29.81F
POTTSTOWN FOG 44 44 100 CALM 29.83S
DOYLESTOWN SUNNY 56 46 69 CALM 29.80S
WILLOW GROVE MOSUNNY 55 48 77 S3 29.82R
NORTH PHILA SUNNY 50 48 93 CALM 29.83S
PHILADELPHIA FOG 45 45 100 CALM 29.83S
SOUTHERN NEW JERSEY
CITY SKY/WX TMP DP RH WIND PRES
POMONA SUNNY 58 50 75 CALM 29.84S
RIO GRANDE* SUNNY 59 48 67 CALM 29.87S
MILLVILLE CLOUDY 50 48 93 CALM 29.83R
WRIGHTSTOWN SUNNY 54 54 100 CALM 29.81S
MOUNT HOLLY SUNNY 54 50 86 CALM 29.83R
TRENTON FOG 46 45 93 S3 29.82R
My Revised Forecasted High Temperatures:
Philadelphia 52-57
Lehigh Valley 45-52
South Jersey 55-60
Delaware 54-59
I'm still confident that N & W will be the last to break into sun and consequently, temperatures will be kept down somewhat. Don't be surprised though to see some low 50's though in places especially near Quakertown and elsewhere. It's going to be take a while for some places to break into the sun but once they do, temperatures will bounce up a good bit.
Rest of the discussion is below!
Welcome to the land of fog. Dense fog advisories are out this AM generally west of the Delaware River for visibilities down to 0. My drive into Center City this morning featured going from mile plus to 0 visibility within the span of a few hundred feet. The worst conditions as of 6 AM are in Quakertown, which is reporting 0 vis and in Valley Forge, which is also featuring 0 visibility.
Given the light flow aloft and at the surface this morning as well as the low sun angle, I believe this fog will hang in a little longer and thus, I'm going to be conservative with high temperatures (around 48-53 for Philadelphia) for the area. If the fog lifts by mid-morning, the temperatures will be higher than that because there are few clouds aloft. However, I do think that low clouds and fog will be the rule as opposed to the exception, especially north and west of the Delaware River for most of the day.
Highs Today
Philadelphia 48-53
Lehigh Valley 45-50
South Jersey 49-54
Delaware 48-53
As for our coastal storm, it will still develop but I tend to think that the best precip chances will be EAST of Philadelphia. A moisture stream is sitting offshore of the Carolinas this morning will get a mid level impulse added to it and it will fire a nice coastal low that will increase the wind for us Tuesday. Yesterday, I stated that I felt the chances of precip (read: RAIN) would be best confined to South Jersey and Delaware and I still feel that to be the case...but I would not be surprised to see some rain drift up into the I-95 corridor or even some of the suburbs. Rain amounts for South Jersey and Delaware look to be 1/4" - 1/2". With a deepening low moving to our east, NW winds will keep the temperatures down Tuesday...mainly in the low 40's with upper 30's for the Lehigh Valley. A few wet snowflakes are possible up towards NYC if enough cold air wraps into this system but I think the best chances for any snow would be over parts of SE New England (and those chances of snow are low).
Temperatures for the rest of the week should be about 5-10 degrees above normal with little in the way of precip until this weekend. Our next storm is looking to threaten in the Saturday-Sunday timeframe but there are a myriad of model solutions for the event at this point. The UK wants to develop another coastal event with the Canadian developing an inland storm system over the South Central US. The GFS develops the bomb over NE PA and shoots it up into New England. Three solutions, three different events that would play out...
The UK would be the quickest (Friday) with light rain and some backlash snow POSSIBLE at the Jersey Shore.
The GFS would be rain with the event ending as snow over the Poconos.
The CMC (Canadian) is too far out to see to be certain of precip type but we could be looking at rain if the low kept an inland track.
Given how we're still stuck in a zonal pattern, things are slow to change. Despite the super cold air up over Alaska (-55 and colder in places), it has not shown any signs of moving towards the US. The long-range models hint at cold coming down the pike towards us around 10 days but given how often they have been showing cold at the 10-14 day range, I'm not optimistic that the pattern changes much. We may see cool downs followed by brief warm ups, but that super cold, at least for now, may stay locked up to the north. If you want to blame anything, blame the jet stream for being zonal for the last seven weeks and keeping the real cold air locked up over Alaska.
