2018 Summer Discussion Thread (Northern Hemisphere)

Today's high in San Diego was 22.2°C (Normal High 23.9°C), back in Phoenix, the high was 40°C (Normal High 41.7°C)

Made it to 99.3F (37.4C) here, heat index peaked at 114.8F (46.0C).

last bit of snow in the Northeast

Back in Phoenix again...

Currently 28.3°C at 3am Pacific (Normal Low 28.9°C)

Forecast High is 42.2°C (Normal High 41.7°C)

25.2C the high today. The temps alone in this warm spell here aren't anything that impressive, but the length of time this has been going on for certainly is.

We've had eight days in a row with highs above 24C now (two days just about failed to reach 25C, but the town of Bingley is at least a degree warmer than where the weather station is anyway so essentially they were 25-26C). I've looked through a lot of hot months from the past to find anything similar and the last time we've had more than seven days above 24C was way back in 1976!

That time we had a crazy 12 days in a row above 26C, we're not going to beat that hot spell for intensity but if tomorrow makes it to 24 again every other day this week is forecast to be warmer, so this could end up our most prolonged spell of warm weather on record. We've just had our warmest May and warmest June and this month's predicted to stay way above average as well, we'd probably need some really hot days (28C+) in there to break the July record but I certainly wouldn't rule it out.

Stark contrast in dew points the past couple days between the NW and the NE:

Today's High was 42.2°C (Normal High 41.7°C)

Currently 30°C at 3am Pacific (Normal Low 29.4°C)

Forecast High is 42.8°C (Normal High 42.2°C)

From NWS Boston discussion. Fog should break:

Trends in the forecast remain on track this morning. Stratus and
fog continues to burn off early this morning. Thus expect dense
fog to be let go across the inland regions. Biggest question
will be for the Islands. High dewpoints with a stagnant airmass
will not offer much in mixing.

As of several days ago, we forecast today to have the first
chance of sprouting convection and that appears to be the case.
Am expecting a fairly active afternoon and evening across
southern New England. After about 2 PM, 700 mb temperatures cool
from +11C down to only +9C which should be just enough to break
the cap and allow scattered thunderstorms to form. ECMWF K
Indices are 37 at 18Z, about the same as with the convection
yesterday in NY state. A weak low pressure trough will be
bisecting the region from NE to SW by mid to late afternoon,
providing forcing with significant moisture flux convergence, as
seen on the GFS. Short range models, including the NSSL HRW,
show scattered thunderstorms on a line from Lowell, MA to
Worcester to Hartford between 18Z and 20Z, then possibly moving
through Boston and northwest RI toward evening. With
precipitable water values above 2", any thunderstorms will
produce locally torrential downpours. Winds aloft are weak, but
with very high CAPE, can`t rule out an isolated wet microburst,
especially in western MA and northern CT.