July 2014: Stalled Front/ Rain Chnaces To End July

[Paul Robison]

Will this front produce multiple thunderstorms as strong----if not STRONGER----as the July 4 storm event?

[Belmer]

Interesting enough, a very strong cold front came through Houston in the summer of 1992. Two weeks later we had Andrew that hit Florida.

[tireman4]

But before the front even starts to hint at coming into the Houston area, we have some really steamy temperatures coming. Upper 90's will be the tone of the day next week.

[srainhoutx]

The warmest weather of the summer season appears on tap this weekend as a robust upper Ridge develops across the Southern Plains. Subsidence, or sinking air should strongly inhibit any chance for much in the way of an isolate pop up pulsing shower along any sea/bay breeze that develops daily into Monday. Next Tuesday things begin to change and rather significantly.

As we have mentioned, a rather unusual weather pattern develops with a potent spinning upper low with its origin across the Arctic and Northern Canada develops near the Great Lakes while the Upper Ridge is pushed W and noses well up into Western Canada carving a deep trough E of the Rockies and ushering in a Polar frontal boundary into the Plains. At the same time deep tropical moisture from the Caribbean Sea enters the Gulf of Mexico as well as moisture from monsoonal activity across Southern Arizona and New Mexico. As has been mentioned there does appear to be some upper level energy dropping SE in the NW flow aloft as well as embedded short wave energy from Mexico. While the various computer guidance remain somewhat mixed, there is rather good agreement that an anomalously cold pool of air by summertime standards drops S from Canada and enters the Southern Plains as well as the Lone Star State. The overnight operational and ensemble guidance suggest that anywhere between 2 to 3 standard deviations below normal daytime and night time temperatures may be possible later next week.

The major fly in the ointment is just where the frontal boundary will hang up or stall. Indications are that the front may stall N of I-10 and S of I-20 or across Central/East Texas and SW Louisiana. A daily push of outflow boundaries from convection along the front will greatly affect where the actual boundary stalls and the focal point of the heaviest rainfall will develop. Another aspect is the development of potential MCS (Mesoscale Convective Systems) upstream or across the Panhandle. With a NW flow aloft established, the movement would be SE toward Central/SE Texas and Louisiana. We just cannot predict with any accuracy if, when and where these potential convective complexes will develop this far in the future. The Weather Prediction Center 7 Day QPF is slowly but surely increasing each day across our Region as more data becomes available. While once Super Typhoon Neoguri is not directly involved in this pattern change, there are elements of that feature that are working in tandem to create a rather unusual mid-summer cold front. I would not be surprised to see rainfall forecast chances increase throughout the weekend for the Tuesday through next Friday time frame. As an interesting note, the analog dates that are at or near the top are July 1961. Those of us old enough to remember will recall an unusual summer cool spell before the SW Caribbean developed the ‘C’ storm around the first of September. Just an interesting tidbit, but certainly not a forecast.

[BiggieSmalls]

What is the date cut off between a late season cold front (Winter 2013-14) and an early season coldfront (Winter 2014-15)?

I'd guess that, unofficially, its around July 4?

[srainhoutx]

What is the date cut off between a late season cold front (Winter 2013-14) and an early season coldfront (Winter 2014-15)?

I'd guess that, unofficially, its around July 4?

http://forums.khou.com/viewtopic.php?t=325&start=0

Our old friend wxdata provided some insight back when 'Doc' Neil was still the Chief Meteorologist for KHOU...

Dr. Frank had gone back and figured that the first morning low into 50's (59 counts!) at IAH was around Sept. 25th-ish. A weaker cool front was possible well before then...

[srainhoutx]

Coastal areas and just inland may need to keep an eye to our E as a TUTT (Tropical Upper Tropospheric Trough) meanders W bound across the Gulf and could offer some enhancement for cooling showers/storms on Sunday into Monday.

[tireman4]

To the still impending cold/cool front (depends on your definition). Tim Heller (KTRK OCM) does not think it will get to Houston.


rare July cool front will plunge southward across the U.S. the middle of next week. Unseasonably cool temperatures are likely from the Midwest into the Deep South.

The cool front could push as far south as Dallas, but it probably won't reach Houston. The front will get close enough to produce widespread showers on Wednesday and Thursday, however. The clouds and rain will keep the temperatures down a few degrees, but don't expect it to be "cooler" around here.


https://www.facebook.com/HellerWeather

My thinking is that models are still waffling on this and we just do not know. I am sure Srain, Andrew and Wxman 57 can chime on this one

[tireman4]

Ok, this is a funny. I had to post this. I just burst out laughing when I read the title...

SummerPolarVortexmageddon II Will Bring Cooler Temperatures Next Week



Weeks after The Vane coined the defining term of summer 2014 — SummerPolarVortexmageddon — another huge cool-down is on tap for next week, and everyone is hopping on the "polar vortex" bandwagon. Imitation is the sincerest form of flattery.

A true polar vortex is essentially a big low pressure center that sits over the North Pole. Every once and a while, it will sort of break apart and turn into a group of smaller low pressure systems circling around the northern hemisphere. When one of these smaller low pressure centers — the "polar vortex" — spins over North America, it can bring exceptionally cold air to its victims and make everyone with an internet connection panic like cavemen seeing a comet for the first time.

What will happen next week is not a polar vortex. At best it's a Hudson Vortex. Manitobavex. But it is not a true polar vortex.


http://thevane.gawker.com/summerpolarvo ... 1603059623

[srainhoutx]

There is not a lot of change via the 12Z of guidance for next week. It is interesting that the frontal boundary is precariously close by for locations from the Panhandle through Central and SE Texas and on into Louisiana. Some of the computer models are suggesting some fairly hefty rainfall totals along that boundary as well as a surge of deeper tropical moisture from the Western Caribbean into the Western Gulf.

[Paul Robison]

There is not a lot of change via the 12Z of guidance for next week. It is interesting that the frontal boundary is precariously close by for locations from the Panhandle through Central and SE Texas and on into Louisiana. Some of the computer models are suggesting some fairly hefty rainfall totals along that boundary as well as a surge of deeper tropical moisture from the Western Caribbean into the Western Gulf.

07112014 19Z Day 3 to 7 Forecast Surface Chart 5dayfcst_wbg_conus.gif

071120014 610analog_off.gif

This, then, is likely to be a significant mesoscale event for the city of Houston?

BTW: What are the models saying about the possibity of a TC developing from this front and heading our way?

[Andrew]

The 12z Euro is suggesting that the front could stall across the central parts of the state. The gfs is more amplified with the trough, but has a further east progression with the wave. Both models show a similar result where the front stalls in the central parts of the state. As of now it looks like central Texas and points north look to be under the gun the most. The Euro showed multiple days of rain around the Fort Worth area as multiple shortwaves rotate SW, leeward of the Rockies. As stated yesterday where the front stalls will be key. Either way the pattern looks supportive for a long term wet event. The key will be in the details.

[Ptarmigan]

The warmest weather of the summer season appears on tap this weekend as a robust upper Ridge develops across the Southern Plains. Subsidence, or sinking air should strongly inhibit any chance for much in the way of an isolate pop up pulsing shower along any sea/bay breeze that develops daily into Monday. Next Tuesday things begin to change and rather significantly.

As we have mentioned, a rather unusual weather pattern develops with a potent spinning upper low with its origin across the Arctic and Northern Canada develops near the Great Lakes while the Upper Ridge is pushed W and noses well up into Western Canada carving a deep trough E of the Rockies and ushering in a Polar frontal boundary into the Plains. At the same time deep tropical moisture from the Caribbean Sea enters the Gulf of Mexico as well as moisture from monsoonal activity across Southern Arizona and New Mexico. As has been mentioned there does appear to be some upper level energy dropping SE in the NW flow aloft as well as embedded short wave energy from Mexico. While the various computer guidance remain somewhat mixed, there is rather good agreement that an anomalously cold pool of air by summertime standards drops S from Canada and enters the Southern Plains as well as the Lone Star State. The overnight operational and ensemble guidance suggest that anywhere between 2 to 3 standard deviations below normal daytime and night time temperatures may be possible later next week.

The major fly in the ointment is just where the frontal boundary will hang up or stall. Indications are that the front may stall N of I-10 and S of I-20 or across Central/East Texas and SW Louisiana. A daily push of outflow boundaries from convection along the front will greatly affect where the actual boundary stalls and the focal point of the heaviest rainfall will develop. Another aspect is the development of potential MCS (Mesoscale Convective Systems) upstream or across the Panhandle. With a NW flow aloft established, the movement would be SE toward Central/SE Texas and Louisiana. We just cannot predict with any accuracy if, when and where these potential convective complexes will develop this far in the future. The Weather Prediction Center 7 Day QPF is slowly but surely increasing each day across our Region as more data becomes available. While once Super Typhoon Neoguri is not directly involved in this pattern change, there are elements of that feature that are working in tandem to create a rather unusual mid-summer cold front. I would not be surprised to see rainfall forecast chances increase throughout the weekend for the Tuesday through next Friday time frame. As an interesting note, the analog dates that are at or near the top are July 1961. Those of us old enough to remember will recall an unusual summer cool spell before the SW Caribbean developed the ‘C’ storm around the first of September. Just an interesting tidbit, but certainly not a forecast.


http://tropic.ssec.wisc.edu/real-time/m ... t72hrs.gif

July 1961 was wet like 1900, 1942, and 2007. Hurricane made landfall later that year.

http://www.srh.noaa.gov/hgx/?n=climate_iah_top10_july

[unome]

as of now, this "cool front" has our heat index lowering to 99 next Wed, I sure hope it drops further south :(

[jasons2k]

NWS graphic says I don't even get a tenth next week. That front will need to come a bit further south to impact Houston:

http://www.srh.noaa.gov/images/fxc/hgx/ ... _full2.jpg

[srainhoutx]

The 12Z GFS panels suggest the shallow front should stall in a NW to SE fashion extending from the front range of the Colorado Rockies into Louisiana. The overnight ensembles are a little more aggressive with bringing unseasonably cooler and drier air as far south as the I-10 Corridor in West Texas and east into Louisiana and stalling the boundary across Central Texas. Typically we see the computer guidance struggle with shallow cool air masses, so I would not be too concerned with these daily flip flopping seen with this system. Another fly in the ointment is the monsoonal activity occurring across Southern Arizona into New Mexico. If additional tropical moisture is pulled E, it tends to set up a great deal of instability along the boundary.

The main take away as the Weather Prediction Center stated in the latest update issued a bit ago is the fact the temperature departures may reach near 2 standard deviations below normal for July standards, or about 10 to 20 degrees below what we typically would expect. What remains to be seen is just where and MCS of QLS events unfold and where the daily outflow boundaries set up. In addition PW’s are expected to increase as a couple waves crossing the Caribbean make their way into the Bay of Campeche. No tropical development with these waves are expected as the Gulf is just too hostile with wind shear. Additional upper air disturbances are expected to drop SE with the NW flow aloft as the Ridge to our W pushes N into Western Canada.

In the shorter term, a trough is heading W across the Gulf ahead of a TUTT low and could bring a chance of showers/storms tomorrow as that feature gets a bit closer to the Texas Coast.

[Paul Robison]

The 12Z GFS panels suggest the shallow front should stall in a NW to SE fashion extending from the front range of the Colorado Rockies into Louisiana. The overnight ensembles are a little more aggressive with bringing unseasonably cooler and drier air as far south as the I-10 Corridor in West Texas and east into Louisiana and stalling the boundary across Central Texas. Typically we see the computer guidance struggle with shallow cool air masses, so I would not be too concerned with these daily flip flopping seen with this system. Another fly in the ointment is the monsoonal activity occurring across Southern Arizona into New Mexico. If additional tropical moisture is pulled E, it tends to set up a great deal of instability along the boundary.

The main take away as the Weather Prediction Center stated in the latest update issued a bit ago is the fact the temperature departures may reach near 2 standard deviations below normal for July standards, or about 10 to 20 degrees below what we typically would expect. What remains to be seen is just where and MCS of QLS events unfold and where the daily outflow boundaries set up. In addition PW’s are expected to increase as a couple waves crossing the Caribbean make their way into the Bay of Campeche. No tropical development with these waves are expected as the Gulf is just too hostile with wind shear. Additional upper air disturbances are expected to drop SE with the NW flow aloft as the Ridge to our W pushes N into Western Canada.

In the shorter term, a trough is heading W across the Gulf ahead of a TUTT low and could bring a chance of showers/storms tomorrow as that feature gets a bit closer to the Texas Coast.

Sounds like a dangerous weather situation for Houstonians to deal with, Srainhoutex. Is this similar to the July 4 event?

[srainhoutx]

Why all the 'drama' Paul Robison? It looks like some much needed rain across the Region with some pleasant cooler air settling fairly far S for July. It is certainly a lot better than a drought and 100F+ temperatures the seem to never end. The severe weather will be across the Mid Atlantic and NE.

[Paul Robison]

Why all the 'drama' Paul Robison? It looks like some much needed rain across the Region with some pleasant cooler air settling fairly far S for July. It is certainly a lot better than a drought and 100F+ temperatures the seem to never end. The severe weather will be across the Mid Atlantic and NE.

Oh, sorry about that, Srainhoutex. Moderator please delete my previous reply.

[cperk]

Why all the 'drama' Paul Robison? It looks like some much needed rain across the Region with some pleasant cooler air settling fairly far S for July. It is certainly a lot better than a drought and 100F+ temperatures the seem to never end. The severe weather will be across the Mid Atlantic and NE.

I'm certainly happy that we appear to be settling into a more typical pattern for our neck of the woods.