July 2023 - General Weather Discussion

[baralheia]

Official temperatures are always measured in the shade.

Well - sort of. So the Mesonet stations themselves are not in the shade; in fact, to the greatest extent possible, they are all located in an open area away from any obstructions that might prevent accurate wind or rainfall measurements. That said, the temperature sensors themselves are shaded in a device called a Solar Radiation Shield, which is a louvered enclosure designed to prevent sunlight or rain from landing on the temperature probe - while still allowing air to flow freely through the enclosure. This helps to prevent sunlight from influencing temperature readings. Many PWSs come with these shields for their temperature sensors, like the Ambient Weather WS-2902C that I have. However, one BIG difference between mine and the equipment used by the Oklahoma Mesonet or NWS is theirs have small fans to continuously circulate air through the shield - this ensures that you're consistently getting a true reading of actual air temperature. Without it, on bright sunny days with little to no wind, the solar radiation shield can trap warmer air inside and that affects the reading.

[fortpatches]

Yep. This is why when people post photos of their vehicle's ambient temperature, it is not even close to the actual air temp. A vehicle facing the sun parked on a blacktop for 3-4 hours can easily show the temp being 120F+. Obviously if it was actually 120 in OKC, it would be a much bigger story.

About this time last year OKC hit a record 110f, my car showed 124f (in the sun) and a colleague's car (similar make/model) showed 118f in the shade about 15ft away.

[OkieHornet]

Official temperatures are always measured in the shade.

My AcuRite has this feature - Two solar panels power the internal fan to maximize ambient temperature accuracy at all hours of the day - so I assume I can't put it in the shade?

[Anonymous.]

The entire thing should be in the shade for the most accurate reading.


SVR watch out again for NW OK, identical to yesterday afternoon. Currently one supercell ongoing E of Dodge City KS. Could see a few more cells pop up from outflow boundaries. Unlikely they hold together beyond NW/N OK, but there is an outside possibility.

[Bunty]

However, if your station comes with a UV sensor and/or solar radiation sensor, it should be in the sun as much as possible. It's only those stations limited to getting temperature and/or humidity in which their sensors must be kept in the shade. Placing them in a tree would be a good, accurate place, more so than under a house eave where it would probably get at least a couple of degrees too hot during part of the day.

[Bunty]

This photo shows an example of an Oklahoma mesonet weather station, in this case, the one in Stillwater. It's located a half mile west of Western St. and a quarter mile north of W. 6th on OSU-owned land. Right after this picture was taken, it started raining. But only turned out to be just a minor shower cloud. The station didn't register so much as .01". Mesonet has 120 stations. https://en.wikipedia.org/wiki/Oklahoma_Mesonet

[SEMIweather]

With dewpoints mixing down into the lower 60's and temperatures barely getting below 80 overnight, today seems like a cinch to be the first 100 degree day of the year. Of course I think I said that twice back in June and it didn't happen on either of those days, so you never know.

[MagzOK]

At 9:04AM, my Ambient Weather station is reading 87.4F up here north of Edmond. Mesonet currents: Kingfisher 87F, Guthrie 85F, NEOKC 84F, SOKC 85F, Norman 83F, El Reno 82F. It is going to be hot.

[Anonymous.]

Thursday night, we should see MCS form across CO and move SE. However, the storms will begin to die out as they get deeper into OK.

This shift in the ridge will help keep temperatures great summer-wise heading into the weekend.

[Anonymous.]

Latest forecast kills storms almost entirely as they enter OK, save for extreme NW/N OK. Great temperatures are still on deck, though!

[BG918]

^ High pressure too strong over Texas?

High pressure over the southern Plains is actually very typical this time of year into early August. This is partly what drives the southwest monsoon.

[Anonymous.]

Supercells have developed across CO and into KS, even a tornado-warned storm heading toward Dodge City KS. Models have leaned a bit further south this afternoon with storm impact/longevity. If OKC is impacted tonight, the best chance will be the northern end of the metro.

As always, the radar will be your friend tonight.


EDIT:
MD is out for the upcoming MCS.

Mesoscale Discussion 1651
NWS Storm Prediction Center Norman OK
0449 PM CDT Thu Jul 20 2023

Areas affected...Southwest Kansas...Oklahoma Panhandle...northern
Texas Panhandle...northwest Oklahoma

Concerning...Severe Thunderstorm Watch 527...

Valid 202149Z - 202345Z

The severe weather threat for Severe Thunderstorm Watch 527
continues.

SUMMARY...All severe hazards will be possible late this afternoon
and evening. Very large hail threat will focus in southwest Kansas
near Dodge City. Tornado threat will focus along a surface boundary
in the combined Panhandles. The primary hazard will eventually be
severe (potentially significant) wind gusts as an MCS organizes and
moves out of southeast Colorado.

DISCUSSION...An ongoing, intense supercell continues across parts of
southwest Kansas just north of Garden City. Hail of 1.75-2.5 inches
has already been reported with this storm and current dual-pol radar
presentation from KDDC would suggest very large hail remains a
potential threat. Furthermore, a tornado has been reported with this
storm as well. This storms and any other that develop nearby are the
greatest short-term severe threat.

Later this evening, convection that is ongoing in eastern Colorado
is expected to grow upscale. Temperatures near 90F and dewpoints in
the upper 60s to low 70s F will support moderate to strong buoyancy
late this afternoon and evening. Combined with strong northwesterly
effective shear, this environment will support potential for an
intense line of storms capable of scattered severe wind gusts (some
of which may exceed 75 mph). Given the linear storm mode expected,
the tornado threat will be somewhat modulated. The greatest threat
for a tornado or two would be along and just north of the surface
boundary into the Texas/Oklahoma Panhandles.

..Wendt.. 07/20/2023

[SEMIweather]

Today, tomorrow, and even Sunday should all be fairly nice by late July standards. Thereafter, the ridge builds back in and turns on the heat for the foreseeable future, with highs in the upper 90's. With the absence of any rain over the last week or so, dewpoints will hopefully stay in the 60's as opposed to the 70's. Rain chances looks very low for the rest of the month.

[BG918]

Today, tomorrow, and even Sunday should all be fairly nice by late July standards. Thereafter, the ridge builds back in and turns on the heat for the foreseeable future, with highs in the upper 90's. With the absence of any rain over the last week or so, dewpoints will hopefully stay in the 60's as opposed to the 70's. Rain chances looks very low for the rest of the month.

Yep the same high pressure that has been cooking Texas will move over Oklahoma for the next two weeks. Some areas there haven't seen any rain in weeks and are very dry. It looks like there could be a pattern change around 8/1 that brings more NW flow and storm chances as the high shifts to the east.

[Bunty]

Friday morning featured not quite the northern half of Oklahoma getting some generous rains fairly evenly distributed, though Tulsa was in a donut hole for less rain. The Mesonet weather station pictured above got 1.09". I got 1.14".

Most of Oklahoma has been well blessed this summer, though not perfectly so from at least one widespread severe storm event, a squall line, associated with unusually high wind. Some people have had very big hail. Anyway, when it gets hot it hasn't been Texas sized heat well into the 100s. Rain has been generous enough to keep the grass green but when it rains, it doesn't do it in 10" amounts like in Vermont.

[BG918]

Friday morning featured not quite the northern half of Oklahoma getting some generous rains fairly evenly distributed, though Tulsa was in a donut hole for less rain. The Mesonet weather station pictured above got 1.09". I got 1.14".

Most of Oklahoma has been well blessed this summer, though not perfectly so from at least one widespread severe storm event, a squall line, associated with unusually high wind. Some people have had very big hail. Anyway, when it gets hot it hasn't been Texas sized heat well into the 100s. Rain has been generous enough to keep the grass green but when it rains, it doesn't do it in 10" amounts like in Vermont.

The Mesonet just estimates totals in between their sites. I had nearly 1.25" in midtown Tulsa but the airport only recorded 0.81". Tulsa is still at a deficit overall compared to the rest of OK this summer so this was definitely needed.

[BG918]

Typical late-July/early-August weather pattern for the next two weeks. Some signs the ridge could break down and shift east allowing more of NW flow toward the first week of August but these highs can be stubborn to move this time of year. If your yard isn’t already browning it will be in a week

[BG918]

Forecast models showing better rainfall chances in mid-August

[SEMIweather]

First 100 degree day at Will Rogers today. We will possibly pick up several more over the next week as it continues to dry out. Looking at mid-to-late next week for a potential breakdown of the ridge which will hopefully open up the door to precipitation chances.

[Anonymous.]

I already saw Bermuda grass burning up today. Crunch crunch

[BG918]

The southern breeze and lower dew points already make the afternoon not feel as hot as last week.

[Pete]

The southern breeze and lower dew points already make the afternoon not feel as hot as last week.

The mornings have actually been pretty pleasant.

[Bill Robertson]

The mornings have actually been pretty pleasant.

They really have!

[SEMIweather]

The past few weeks have strengthened my belief that a 100/65 temperature/dewpoint spread is preferable to a 90/75 one. The last several days haven't been too bad at all, IMO. Of course, the downside to the less humid pattern we're currently in is that it's very difficult to get any meaningful precipitation.

[BG918]

Heat dome strengthens this week but still showing signs of shifting toward next weekend with rain chances returning early next week