September 2015: Pleasant Weather To End The Month

[ticka1]

one week away new month - will we see Fall/Autumn or will tropical action show up here? Or will hot summer days continue!

[galvbay]

ticka1....I'm ready for some sub 90 weather!

[srainhoutx]

A rather strong upper trough and associated shortwave should begin to drop SE into the Pacific Northwest ushering in a fairly potent early season Polar front across the Northern tier of the United States. Heavy rainfall at the lower elevations with higher elevation snow should bring some relief to the wildfires across the NW. Closer to home, an upper low/trough appears to be organizing over Louisiana and is stretched back into the NW Gulf of Mexico. This shear axis/upper level low is expected to slowly meander to the West and possibly increase our rain chances early to mid next week as we begin September. The best chance for rain looks to be along the Coastal tier of Counties and offshore where the higher moisture is expected to slowly move toward the Coast. Inland areas along and N of the Highway 59 Corridor may not see much if any rainfall Monday into Tuesday. The shortwave to our NW is expected to pass well to the N of Texas, but could push a frontal boundary S near the Red River. The upper low/trough looks to open up and drift back E as what ever is left of Erika slowly moves over or just West of the Florida Peninsula. Heavy rainfall is expected to impact Florida next week, but no real development is expected from Erika. Typically we begin to see signs of more active cold fronts as September progresses steadily toward October. It's also getting to be that time of year when we need to monitor the Eastern Pacific for any tropical troubles that could spread moisture across Mexico as the Fall season cool fronts as well as a Western trough develops allowing for any tropical storms to 're curve back into Mexico. The days are getting shorter and the longwave pattern across the Pacific Ocean begin to shorten the further we transition into Meteorological Fall that begins September 1st.

[texoz]

I saw that the first winter storm watch (Alaska) for the season was issued. Definitely a sign that summer is losing its grip.

[srainhoutx]

The global dynamical and ensemble guidance continue to advertise some rather significant changes ahead as we head toward a meteorological Fall. The tropical activity across the Pacific Ocean is offering us some clues as to what may expect regarding the sensible weather across Texas and the Gulf Coast as well as East of the Continental Divide near the September 6th-10th timeframe. Several features are beginning to show us this change in the medium to long range forecasting schemes. Three areas that I have been watching rather carefully that past several days is a buckling of the Polar and Sub Tropical Jet streams as well as a robust Convectively Coupled Kelvin Wave and a wet phase of the MJO that is allowing tropical cyclones to increase in intensity and numbers across the Central and Eastern Pacific Basins. El Nino is beginning to show its hand as what we might expect as Fall approaches. It appears the buckling of the various jet stream pattern has legs and a parade of shortwaves look to begin diving S and E out of the Arctic and the Canadian Prairies toward the Northern tier of the United States and the Great Lakes Region. Attending frontal boundaries should accompany these features at the higher latitudes. Regarding the Tropical Eastern Pacific as well as the Western Atlantic Basins, there is growing concern of re-curving Eastern Pacific tropical cyclones toward Mexico bringing their mid/upper level moisture across Mexico into New Mexico, Southern Plains and portions of Texas as frontal boundaries near the area and likely move slowly S toward the Gulf Coast. There is also the potential of tropical troubles brewing a bit closer to home in the Bay of Campeche/SW Gulf of Mexico during the second week of September. As the CCKW and MJO wet phase pulse nears our backyard, attention may need to focus to our S near the Yucatan Peninsula and Bay of Campeche. It's that time of year when we near climatological peak tropical season and it is not out of the question that something may attempt to spin up closer to home increasing our rain chances at the very least.

[srainhoutx]

Afternoon briefing from Jeff:

The high mountains of the Dominican Republic and Haiti along with strong vertical wind shear resulted in the dissipation of the low level center associated with tropical storm Erika early Saturday. The wave axis is currently moving into the SE Gulf of Mexico, but due to continued strong upper level winds, no regeneration of this system is expected.

Tropical Storm Fred:
A strong tropical wave moved off the coast of Africa yesterday and has quickly developed into a tropical storm and in fact based on the current organization may be attempting to intensify into a hurricane. Fred will be moving NW and then turn westward over the next 3-4 days followed by a turn to the NW and recurve over the open Atlantic due to a trough along 50W. Hurricane Warnings are currently in affect for the Cape Verde Islands and as best as anyone can tell this is the first time hurricane warnings have been issued for these islands.

Locally:
An upper level trough located along the US Gulf coast will gradually move westward allowing tropical moisture to surge into the area starting on Monday and peaking Tuesday/Wednesday. Rain chances will be increasing especially Tuesday/Wednesday as this moisture surges inland.

[srainhoutx]

Morning briefing from Jeff:

Upper level trough that has formed over SC TX will only slowly move eastward over the next few days resulting in good chances for showers and thunderstorms especially south of I-10.

Radar this morning shows a large complex of showers and thunderstorms over the NW Gulf of Mexico south of Matagorda Bay with a couple of isolated storms over Galveston Bay. Activity has moved well inland around Matagorda Bay and extends from over 100 miles offshore to SW Lavaca County. Tropical air mass has spread inland on the eastern flank of the S TX upper level trough with favorable upper air divergence located over the Gulf waters helping to maintain the current convective area.

Expect the Gulf activity to spread inland this morning and as temperatures rise into the low to mid 80’s additional activity will develop inland. Most of the rainfall will focus along the coast and just offshore where low level speed convergence will be maximized with more scattered activity inland. Given the deep tropical moisture in place very heavy rainfall rates of 1-3 inches per hour can be expected under the stronger storms which may lead to street flooding. Areas over Calhoun and southern Jackson Counties have been showing upwards of 2 in per hr rainfall rates this morning.

Upper trough slowly progresses eastward and this will keep rain chances in the forecast into Wednesday and Thursday as the air mass remains moist and unstable. Upper low should meander eastward toward the end of the week…but there is much spread in how quickly this happens and if the feature then drifts back westward this weekend. Will keep rain chances 20-30% from Thursday-Sunday, but this could change to higher chances should the low meander over SE TX.

[jasons2k]

Rain is going all around me, a big donut of nothing for most of North Harris/Montgomery counties.

[BlueJay]

Agreed, jasons. 0.00 inches of rain for us today.

[Katdaddy]

A wet morning across Houston metro and along the coastal counties with some locally heavy rains. Picked up .77" around 4:20AM this morning. Additional locally heavy rains will be possible this afternoon. The upper low is forecast to slowly fill in as we approach the holiday weekend leading to a lowering of rain chances. This morning's Houston-Galveston AFD mentions the potential of cold front in the extended period. Fall 2015 is not far away.

OF NOTE IN THIS PART OF THE EXTENDED FCST - A COLD FRONT MAYBE PERHAPS NEXT FRI? WHILE THE ECMWF LOOKS TOTALLY IN FAVOR WITH THIS THE GFS IS NOT EXACTLY DISCOURAGING EITHER. ALSO THE TIMING IS ABOUT 4 DAYS AHEAD OF THE CLIMATOLOGICAL NORM FOR COLD FRONTS IN SE TX (WHICH IS SEPT 15TH). SO I GUESS WE SHALL SEE...

[Stormrider]

This morning's round of rain caused some street flooding in Galveston.

[wxman57]

I measured just over 8" in August, bringing my total to 50.98" for the year at the end of August. Another .7" this morning.

[srainhoutx]

Beginning to see some signs of the pattern changing the week after Labor Day with a cool front clearing the Coast and the possibly the first legitimate Fall cold front arriving near mid September possibly dropping our night time lows into the upper 50's at least.

[sambucol]

Beginning to see some signs of the pattern changing the week after Labor Day with a cool front clearing the Coast and the possibly the first legitimate Fall cold front arriving near mid September possibly dropping our night time lows into the upper 50's at least.

That sounds great! I hope it's the beginning of a chillier fall and much colder winter!!

[BlueJay]

No rain for us today.

[Kludge]

I measured just over 8" in August, bringing my total to 50.98" for the year at the end of August. Another .7" this morning.

Well-then, you had more this morning than I measured since July 4. Actually 50% more.

Technically we're both in the same CWA. [Ed Mahmoud was quick to debate that geographical gerrymandering.]

Note that the 44" we've had this year puts us a little above our total average rainfall. But boy, when the spigot turned off, it welded shut.

Someone around here referred to this as a "flash-drought". Pretty accurate. It's nowhere near as bad as 2011, but one doesn't have to use much imagination to relive the feeling.

I fear we're into a sort-of mini-drought-feedback-dome here now. Someone should study the phenomenon. Clusters of impressive storms move towards this area, only to poof... and then sometimes reform just a few miles away. Historical radar gifs will verify this.

Trying not to whine here... but my jealousy of your bountiful summer is overwhelming. Our delight at the wonderful replenishment of the greenery in this area early this year has given way to intense frustration.

Let's all pray for continually progressive weather patterns... such that none of us get stuck in mud or dust.

[wxman57]

Here's a plot of 2015 rain vs. 2014 from my rainfall spreadsheet. July was fairly dry, but August was very wet. I'm midway between the SW corner of 610 ad the SW corner of Beltway 8.

[srainhoutx]

A very moist tropical airmass remains in place this morning with PW's in excess of 2 inches across the Coastal and Metro Houston Area. Heat of the day showers and thunderstorms look to be in the offing throughout the Labor Day Holiday Weekend. Tropical Storm Kevin in the Eastern Pacific is slowly advancing toward the Baja Peninsula with its mid/upper level moisture spreading NE. A trough with rather chilly air aloft continues to dig S along the Great Basin bring rain and higher elevation snows across British Columbia and the Cascades. Areas across the Northern Rockies could see their first significant snowfall of the season as well. The Global ensembles continue to advertise the longwave pattern across the Pacific Ocean is reshuffling as tropical cyclones in the Central and Eastern Pacific continue to churn. A combination of a rather impressive early Fall season storm complex moving across the Northern tier of the United States and abundant tropical moisture associated with the sub tropical jet and a frontal boundary nearing Texas mid to late next week suggests increasing rain chance with the potential for greater areal coverage and perhaps rounds of heavier more widespread rainfall may need to be included in the upcoming sensible weather forecasts. Enjoy the Holiday Weekend and the warm temperatures. The first shot of early Fall season cooler air may arrive as we near mid September.

[djjordan]

I for one am ready for fall weather. Bring it on!!!! Happy Labor Day Weekend everyone.

[srainhoutx]

The overnight ensemble guidance continues to paint a rather significant pattern change across North America with a bit of an unseasonably early trough digging S across the Central United States and lowering pressures at the surface as well as aloft across Texas next week continuing until at least mid September. If the various computers schemes are correct, we could see a return to a very unsettled weather pattern across the Lone Star State into Louisiana including the potential for heavy rainfall and possibly strong to severe thunderstorms by later next week.