Kirk Mellish's Weather Commentary 

Cold in and out

  • 5:57 pm Sunday, October 29th, 2017 by Kirk Mellish

The weak La Nina base state to the atmosphere continues in front of us, as cold comes but can not hold.

Instead we progress back to the trough and cool west ridge and warm east pattern we’ve seen most of September and October. So temperatures here quickly begin to moderate:

But longer term the ridge shrinks over the south as the pattern tries to shift to some weak ridging out west:

So cooler air presses into the Northern U.S. and the unseasonably warm weather here backs off:

This pattern of brief cool spells interrupted by above normal temperatures looks like it will largely persist [More]

Looking only at current La Nina status for winter

  • 5:43 pm Tuesday, October 24th, 2017 by Kirk Mellish

If NOTHING else is considered, here’s a shake down of the winter based ONLY off the current shape of the Pacific in the La Nina zone. And by the way, you never make a forecast by looking at only one input. So this is but one signal, and it may look different by forecast issuance time.

Above are past years (or analogs) that look similar in Pacific to this year… as of now.

RESULTANT UPPER AIR PATTERN:

Ridges west and trough over Great Lakes region.

RESULTANT SURFACE TEMP ANOMALY:

No two are ever exactly alike, but typically in a La Nina December is the warmest [More]

Warm November not expected

  • 11:11 am Sunday, October 22nd, 2017 by Kirk Mellish

The outlook does not call for a cold month of November per se, but it does NOT look like the abnormally warm weather pattern of September to first half of October will continue.

I’ve been signalling this trend on Twitter for many weeks now, thanks to using old school teleconnection methods like the re-curving Pacific typhoon rule, the Bearing Straits low rule, Alaska-West Canada ridge and hints at a +PNA -NAO -EPO/WPO.

You can google those if interested. But they all suggest an upper-air jet stream pattern with some ridging west and a trough east as shown on previous posts.

As an over [More]

Big weather changes again next week

  • 9:52 am Thursday, October 19th, 2017 by Kirk Mellish

A warming trend is upon us, but already the end of that is in sight. Some of the chilliest temperatures of the season to date on the way by next Wednesday and Thursday. But no freeze expected for ATLANTA as of now with lows of 36-45. Spotty light frost might be possible by Friday.

Most of the country has not had a first freeze yet this autumn:

Some hefty rain totals are possible in the transition Monday into the first part of Tuesday.

We go from upper-level high pressure ridge aloft today to a deep trough late Wednesday as two short-waves… one in [More]

Humidity and heat relief, fall will return

  • 3:20 pm Wednesday, October 11th, 2017 by Kirk Mellish

One front is coming through this Wednesday night and will lower humidity from the extremes of this week, not exactly dry air, but less humid Thursday:

However, as I discussed in my radio 5-day forecast this morning on “Atlanta’s Morning News”, a wave of low pressure forms on the front and brings back some moisture from the Atlantic Friday into the weekend as a weak wedge pattern forms:

So the humidity on the weekend will also be less than the start of this week, but still not quite dry air. A few scattered showers Friday with the wave but most of us [More]

Updated modeling on winter

  • 8:32 am Tuesday, October 10th, 2017 by Kirk Mellish

Considerable agreement among the various models on both the temperature and precipitation pattern. It definitely has a LaNina look to it.

The upper left panels (NMME) is the blend of U.S. models, the lower right panels are the international model blend (IMME).

DJF TEMPERATURE AVERAGE DEPARTURE FROM NORMAL:

DJF PRECIPITATION AVERAGE DEPARTURE FROM NORMAL:

Suggests the primary jet stream storm track just to our north and west with a SE upper ridge. This much agreement doesn’t happen that often. But, I have seen strong agreement be wrong in the past, so it’s not a lock.

At least for now, no help from the sun for [More]

Nate is here

  • 10:04 am Sunday, October 8th, 2017 by Kirk Mellish

As I forecast yesterday most of us will just have a day with rain and occasional wind gusts of a non-severe nature.

Most of the metro area will have periodic wind gusts under 35 mph, but a few gusts to near 50 mph can not be ruled out far west and north suburbs and into the mountains. A small brief isolated weak tornado can not be ruled out anywhere this afternoon or early evening, but mostly east half of Georgia.

A Flash Flood Watch is in effect through Monday morning mainly north of I-85.

POINT FORECAST FOR REFERENCE…

MIDOWN/BUCKHEAD AREA:

ADAIRSVILLE AREA:

ECMWF MODEL WIND GUST [More]

Hurricane Nate

  • 5:00 pm Saturday, October 7th, 2017 by Kirk Mellish

Nate makes initial landfall tonight!

Most areas of metro Atlanta should have winds near or BELOW tropical storm strength. But, some gusts of 35-40 mph are possible. The highest level risk for downed trees and power outages still looks to be in the mountains and in the far West and North/NW suburbs. BUT just looks like isolated cases except for the mountains. (This is opposite of how Irma impacted the area, where the worst was South and East of downtown).

For most of the area the expected winds will be no worse than a strong thunderstorm, or a breezy day anytime of [More]

Nate on the way

  • 5:00 pm Friday, October 6th, 2017 by Kirk Mellish

It’s a tropical storm now but NHC forecast strengthening to a minimal 80 mph hurricane CAT 1 before making landfall late Saturday night or early Sunday morning in SE Louisiana and Southern Mississippi.

The models are in good agreement on the track, which has been shifted slightly east and sped up, but future intensity is highly uncertain due to competing and conflicting influences.

The greatest risk for downed trees and power loss in some spots is in the mountains and far North and West suburbs. This reminds me of a flip of Irma… instead of worst I-85 south and east then, this [More]

Nate or it’s moisture still loom even here

  • 5:08 pm Thursday, October 5th, 2017 by Kirk Mellish

However, this is far from certain. NHC still has a CAT 1 hurricane, even a Tropical Storm can have significant impacts in LA/MS/AL and West FL Pan Handle.

More data from hurricane hunter planes should help firm up the forecast between now and Saturday afternoon:

It has been 15 years since a hurricane last hit that part of the Gulf where Nate is predicted to go:

With Nate still being so disorganized and so far away, the details of impacts on the U.S. coast and here in Atlanta and the rest of Georgia remain uncertain. Much will depend on how strong it gets [More]