Upton's AFD regarding the heat mid-late week:
A highly anomalous amplified upper flow will be featured across
the country from mid to late week, with a trough out west and a
a high centered over the Ohio and Tennessee Valleys. Heights
are greater than 594 dm, about 2 SD above normal, and 85H temps
on Thursday on the latest 00Z GFS are at or just above 22C.
There is still some uncertainty with the upper ridge strength
and magnitude as disturbances round the ridge across the
Northeast. The 00Z GFS is still supporting a convective complex
dropping across the Northeast Tuesday night into Wednesday
morning, sending a back door cold front through the area.
NBM temperatures for the long term were a few degrees too warm,
especially for Thursday and Friday, most notably with a 105
high temperature near KTEB on Thursday. This seems too high
with the aforementioned 22C at 85H. More realistic highs for NE
NJ are upper 90s to lower 100s, slightly lower for NYC with the
rest of the area in the middle to upper 90s, except cooler at
the immediate coast. Slightly cooler readings are expected
region-wide Friday. Record highs during this time are mainly
100 plus. So some pretty stout records are in place. If the NBM
highs pan out however, they would tie or break records for
Thursday.
Max heat index values reach Heat Advisory criteria (95-99 for
two days, 100-104 for one day) by Wednesday, with isolated
readings reaching Extreme Heat Warning criteria (105+).
Thursday will see widespread 105+ across the forecast area.
Lower max heat index values expected Friday, with Heat Advisory
possible for most places except NE NJ, NYC, and western Long
Island, where Extreme Heat Warnings may be possible once again.
