July 16, 2013: Heat Continues Through Saturday

Forecast Highlights:

The heat wave that began on Sunday continued yesterday, with even hotter temperatures peaking in the mid to upper 90s except for the coast and interior locations and heat index values in the low 100s. Slightly cooler temperatures are expected today and tomorrow, but with even hotter temperatures for the second half of the week with some locations approaching 100 degrees. The heat will end this weekend with the passage of a cold front that may produce severe weather, possibly widespread, across the region.

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Monday, July 15 Observations:

As ridging continued to build into the region, hot and humid conditions intensified compared to Sunday. Light NW winds were observed along with mostly sunny skies, with highs reaching the low to mid 90s for most of the area with mid to upper 90s in the immediate NYC area. Along with humid conditions, heat index values reached the upper 90s to low 100s for most. The hottest temperature in the area was 97 degrees in Newark, NJ.


Today - Friday: Heat Continues

The latest 6z GFS initialized 500mb geopotential heights and vorticity map was posted to the left; the map shows a massive 594+ dm ridge sitting on top of the region, with the ridge slowly shifting to the west. On Wednesday, a shortwave moving through southern Canada will flatten the ridge, with a more zonal flow setting up for the late week as a trough slowly sinks southeast into the region. 850mb temperatures will peak in the 16-20C range through Wednesday and the 18-22C range on Thursday and Friday, which along with mostly to partly sunny skies as well as NW winds today and west-SW winds for the rest of the week, will result in hot and humid conditions continuing through the rest of the week.

Mostly to partly sunny skies are expected today again with highs reaching the low to mid 90s near the coast and inland and the mid to upper 90s elsewhere; a NNW wind is expected at 5-10 mph, with slightly lower humidity compared to yesterday. The wind direction is expected to switch to the west on Wednesday and the WSW on Thursday and Friday, with slightly hotter temperatures reaching the low to mid 90s near the coast and the mid to upper 90s for the rest of the area, peaking in northeast NJ in the upper 90s to near 100 degrees. Increased humidity is expected as well with heat index values in the low to mid 100s. Most of the area is expected to be dry, although an isolated afternoon thunderstorm can't be ruled out.


Weekend - Next Week: Storms, Possibly Severe, Then Cooler

The next cold front will approach during the weekend, likely moving through on Saturday. Widespread thunderstorms, some of them strong to severe, are expected with the frontal passage, focusing primarily north of NYC. Following the frontal passage, a period of average to slightly below average temperatures is expected for Sunday into parts of next week with lower humidity and drier conditions, as lows return into the 50s and low-mid 60s with highs in the 80s and possibly upper 70s.