Woznicki - Boston, Mass
Current Analysis & Forecast for the Rest of the Day:
1000-500 mb thickness charts continue to show the strong ridge over the New England area today, as temperatures soar into the upper 80s - marking one of the hottest Boston Marathon days on record. Current surface observations and visible satellite indicate a lot of solar heating available as cloud cover is confined to areas just east of the New England area. Temperatures are exceeding 80 degrees in most areas, and some stations are already in the upper 80s. Extreme coastal areas are slightly cooler as a sea breeze front has set up (mid 70s). The highest temperatures look to be in the middle Connecticut valley. Winds are light from 5-10 knots currently, but will begin to pick up as stronger winds above the surface begin to mix down (red flag warning for much of the area). The temperatures are also expected to mix down in the boundary layer, as the 12 UTC sounding indicates they were nearing 25 degrees Celsius at 12 UTC this morning.
1743 UTC Surface Observations
12 UTC Sounding Upton, NY
A weak cold front associated with the low pressure system to the North will pass over the area late this evening, but a temperature drop will be the only significant impact. The front looks to pass after the 00 UTC hour this evening, as winds shift at the surface to a much more northerly component. Frontogenesis seems to be fairly strong over the area currently, as shown on the SPC mesoanalysis page. Extreme lack of moisture with the passage of this front should keep the area dry for most of the period. Model soundings do indicate, however, that there are some slight values of CAPE, and this could lead to some rumbles of thunder if any convection does develop. Cold air behind the front will affect temperatures for the next few days.
Current Surface Frontogenesis
Precipitable Water for 22 UTC this evening.
Tuesday 12 UTC - Thursday Forecast:
The passage of the cold front brings 1000-500 mb heights down fairly significantly with northwest winds and CAA. Highs tomorrow will be nearly 10 degrees cooler area-wide, but few clouds are expected as no large scale Q-G forcing is available. Winds will be strong at the surface throughout the majority of the day (out of the northwest at around 25 knots). Temperatures will continue to plummet into Tuesday night, as lows on Wednesday morning could be down into the mid to lower 40s. Wednesday's highs may not even reach 60 degrees, but it should be the final day of cooler weather. Zonal flow returns by Wednesday night and Thursday, and highs should be back up into the 70s. Sea breeze is also possible near the coast on Thursday, as temperature gradients should be very significant (sea surface temperatures near 11 degrees Celsius).
Warm-Air Advection Wednesday 00 UTC.
Friday - Sunday Forecast:
Warm temperatures continue with the zonal flow on Friday and early Saturday until a short wave low-pressure system appraches Saturday night and Sunday. Good WAA and vorticity advection look to be the case as this storm approaches, and this could bring significant precipitation to the area a early as early Sunday morning. Most of the precip looks to hold off, for now, into the earlier part of the next work week. This looks to be a fairly substantial system that has the potential to stick around for a while as is is blocked by the ridge in the mid-Atlantic.
Monday 00 UTC GFS Surface Forecast
Monday, April 16th:
Record Highs were reached on the day of the Boston Marathon, with temperatures reaching into the lower 90s in some areas (especially in the Connecticut valley. Lower, non-record, highs were felt near the southeast coastal areas as a sea breeze kicked in into the afternoon hours. Descent winds of up to 20 knots and dew points in the lower 40s throughout much of the area warranted a red flag warning for the area. I have thankfully not been able to find any fire reports. Temperatures were able to cool off into the upper 50s overnight, as clear, dry conditions prevailed. The Boston Airport did show a trace of precipitation, but no evidence of any showers is evident on radar reflectivity. No real forcing for vertical motion was observed.
Hartford, Connecticut - 92 F - Record
Boston Airport - 88 F - Record
Providence, RI - 83 F
Worcester, MA - 88 F - Record
Surface Obs at 20 UTC on 4/16
Tuesday, April 17th - Wednesday, April 18th:
Temperatures were quite a bit higher than forecasted, as the weak front seemed to stall out just west of the Boston area. Highs were near and above 80 in most locations. Relative humidities were in the teens, and wind gusts were nearing 25 knots. Frontogenesis at 00 UTC on Tuesday (forecasted time of front arrival) was maximized just west of the area. The front did eventually move through around 23 UTC on Tuesday, and temperatures quickly dropped in the mid 60s. Temperatures continued to drop throughout the night, and the high temperature yesterday was reached in the early morning hours (56 at Boston Airport). Temperatures fell throughout the day with cold-air advection behind the front, and eventually hit a low this morning of 47. The main cause for the slowing down of the front is the ridge in the Atlantic that continues to block the pattern.
Frontogenesis at the Surface (00 UTC Tuesday) - Front Stalled out Just North and West of the Area
Frontogenesis at 23 UTC Tuesday as the front has passed and cooler air is moving in.
Blocking Ridge Right at the Time of Frontal Passage
Strong Cold-Air Advection after frontal passage at 850 mb.
Today: We are back up near 60 so far today. Winds are less than 10 knots today, and relative humidities are back up enough to lower the fire danger.