It's now the hottest month of the year for New England. This July in New England is currently looking to shape up how one would expect July to be in the region with sustained warmth with bouts of thunderstorms and only brief, but still warm, cool downs. See the details below.
TEMPERATURES
New England is starting the month with a continuation of the general pattern that ended June. The flow is mostly zonal (with the jet stream generally flat over New England). This is leading to a steady progression of high and low pressure through the region. New England is currently under high pressure through the middle of this week.
This high will slide offshore as the next disturbance approaches. This will bring typical summer temperatures to New England, with increases in heat and humidity as disturbances lift warm fronts into New England. Humidity levels will fall temporarily after cold front passages, but temperatures look to remain warm, very typical of summer cold fronts.
Heading into this weekend and into the second week of the month (July 7-12), there is good agreement among models that ridges will form along the east and west coasts with a trough over the center of the country at the mid-levels. This will likely bring continued above average warmth that will build this weekend.
500mb height anomaly for showing above average heights over the east and west with troughing in the central United States. Above average heights favor above average temperatures:
There are currently no signals for a significant heat wave next week like the one seen in the middle of June. Currently, the greater chance for significant heat will be within the western ridge rather than the eastern ridge. This comes as continued frontal boundary passages and unsettled weather may keep temperatures in check.
The trough in the center of the country may still influence the northeast as the mean ridge in the east likely won't be centered over New England. As of now, odds favor slightly above average temperatures rather than well above average.
Heading deeper into July, above average heights at the mid-levels are expected to expand into the center of the country with the east and west coasts remaining above average. This would lead to continued above average warmth for New England. This broad above average height level can be seen in the Climate Prediction Center's 8-14 day outlook, which favors above average warmth for nearly the entire United States.
The second half of the month may see general ridging over the east weaken. Ridging over the west may remain in place during this time, though the timing and placement of this pattern evolution is uncertain, which is expected now looking weeks ahead. Overall, long-term signals point to continued widespread warmth across the United States, which should be expected given late July is the warmest time of the year. It looks like the hottest temperatures (relative to average) may remain in the west.
Overall, we’re predicting an above average July. Signals point toward more sustained summer warmth with only brief cool downs as frontal passages and times of unsettled weather continue. This unsettled weather may help keep temperatures from reaching their full potential at times. Guidance is pointing toward a rather typical July for New England.
PRECIPITATION
The general pattern over the past week plus for New England has been for high and low pressure to trade places as zonal flow pushes these features across the county. This is continuing with high pressure overhead to start the month. This will be replaced by more unsettled weather for late this week and into next week as continued surface fronts cross New England from systems tracking across the Great Lakes.
This generally brings New England bouts of unsettled weather, but limited washout potential. From Thursday onward this week into the weekend, periods of showers and storms will be possible, but no day will see an all day rainfall.
Daily weather maps from Thursday (7/4) to Tuesday (7/9) showing a series of surface fronts hanging around New England, which will lead to periods of unsettled weather:
Overall, guidance is leaning toward slightly above average precipitation with bouts of unsettled weather, especially in the first half of the month. Depending on how things shake out, there could be a drier second half of the month, which may help offset the wetter first half. There are no strong signals for above or below average rainfall.
LOOKING BACK
In our June outlook, we predicted a near average month with odds favoring temperatures on the warmer side of seasonable. We specifically called for a warm start and end with a cool down somewhere in the middle (which may have been trying to get a bit too specific in a monthly outlook). There was a cool down after a warm start in week two.
Then came a major heat wave, which upended the near average forecast for some places. Hartford, Bridgeport and Caribou all saw their hottest June on record thanks to this heat wave. Outside of this heat wave, temperatures were generally up and down, which did lead to a slightly warmer than average month overall.
