The unusually cool air which spread into Texas Friday behind a strong cold front has now exited to the northeast. In its place, a flow off the Gulf of Mexico has brought the return of warmer and more humid air. Monday's weather maps showed winds in the middle and upper atmosphere flowing from west to east across the southern US thanks to a large trough of low pressure along the West Coast and a ridge of high pressure located over the Gulf of Mexico and the western Caribbean Sea. The large ridge of high pressure responsible for the extended summer pattern has finally weakened and shifted southeast.
Late morning satellite images showed a large area of clouds covering most of Texas. These clouds are the result of considerable Pacific moisture being carried east along the mid and upper-level winds and moisture spreading north in the lower atmosphere. Our sky is expected to stay mostly cloudy to cloudy today through Tuesday as additional moisture spreads over the area. Today's analysis showed several weak disturbances embedded in the westerly wind flow tracking east out of northern Mexico. These disturbances have been causing the development of widespread light rain showers across much of West Texas, including the northern and western Hill Country overnight and this morning. Rain amounts have generally only totaled a few hundredths of an inch.
For this afternoon, occasional light rain showers and isolated thunderstorms are forecast across the entire region as additional disturbances move across the area. The highest probability for rain will be across the northern Hill Country and the middle Texas coast, while just a slight chance for rain is predicted across Central Texas. For locations that do see rain, totals are forecast to average around a quarter inch or less, with isolated totals to around a half inch possible. Afternoon temperatures will range from the upper 70s north, to the middle 80s across Central Texas to near 88-90 degrees across the coastal plains. Just a slight chance for light rain is forecast Monday night. Lows Tuesday morning will range from the upper 60s west to the mid-70s near the coast.
On Tuesday, there will be a slight chance for rain showers across the area in the morning. However, the chance for rain showers and scattered thunderstorms looks to increase to 30-40 percent in the afternoon as the trough along the West Coast moves into the Desert Southwest. Some of these storms could become strong, producing gusty winds and even some small hail. Tuesday's temperature is forecast to warm to around 90 degrees.
Tuesday night into Wednesday morning, the probability for rain showers and scattered thunderstorms is forecast to increase to around 60-70 percent when a cold front sinks south out of northwest Texas. The front is predicted to reach the northern Hill Country Tuesday evening, with the front tracking southeast overnight and moving off the coast after sunrise Wednesday. With a very moist air mass in place, forecasts are calling for general totals in the range of 0.5 to 1 inch. Isolated totals to near 2 inches will also be possible. Lows Wednesday morning will range from the upper 50s across the Hill Country to the low 60s across Central Texas to the upper 60s near the coast.
NWS Rainfall Forecast for the Period 7 pm Monday through 7 pm Wednesday:
Wednesday's weather is expected to start off cloudy, with a slight chance for a few rain showers across the Hill Country and Central Texas regions. There will be a 50 percent chance for rain and thunderstorms across the coastal plains. The chance for rain will diminish and the sky should become mostly sunny across the Hill Country and Central Texas Wednesday afternoon. A few shows are expected to linger across the coastal plains through late afternoon. Wednesday's temperatures will be cooler, with highs generally in the upper 60s to low 70s. Expect a breezy north wind at 10-15 mph through late afternoon. The sky will be partly cloudy Wednesday night. Lows Thursday morning will include the upper 40s across the Hill Country, the low and mid-50s across Central Texas and the upper 50s across the coastal plains.
The sky will be partly cloudy sky across the region Thursday through Saturday. High temperatures in the mid-70s Thursday should warm into the low 80s Friday and into the upper 80s on Saturday. Lows Friday morning will mainly be in the mid-50s. Lows Saturday and Sunday mornings will be in the 60s. High temperatures Sunday will again be in the upper 80s.
Today's forecast solutions call for a vigorous trough of low pressure to sink southeast out of the northern Rockies on Sunday. The trough is forecast to reach the southern Plains Monday, then exit to the northeast. As the system approaches Texas on Sunday, considerable moisture will be drawn north from the Gulf. There will be a 40 percent chance for rain showers and thunderstorms Sunday afternoon, with the probability for rain increasing Sunday night into Monday morning. The chance for rain looks to end from west to east Monday afternoon behind a fairly strong cold front. Rain amounts are currently forecast to average between 0.25 and 0.5 inches, but these totals could go higher as the forecast models get a better handle on the moisture return.
Monday's cold front will bring cooler temperatures that should last through much of the week. High temperatures are forecast to be in the 70s to near 80 degrees, with low temperatures mostly in the 50s, with some 40s across the Hill Country. Dry and sunny weather is forecast next Tuesday through Friday.
Tropical Weather Outlook
Weather conditions are currently quiet across the tropical Atlantic, the Caribbean Sea and the Gulf of Mexico. However, forecasters are keeping a close watch on an area of disorganized showers and thunderstorms over the southwestern Caribbean Sea, Gulf of Honduras, and parts of Central America. This disturbed weather is associated with a broad area of low pressure located inland over northwestern Honduras. This system will move west-northwestward across southern Belize, northern Guatemala, and southeastern Mexico during the next couple of days, preventing tropical cyclone formation during that time. By Wednesday, however, the low is forecast to emerge over the southern Bay of Campeche where conditions could become a little more conducive for some further organization to occur. NHC forecasters are only giving this system a 20 percent chance for development over the next 5 days. Should something develop over the Bay of Campeche, forecasts call for the system to track northwest toward the northeastern coast of Mexico late week.
NHC is monitoring a tropical wave accompanied by a small low pressure system located over the central tropical Atlantic. This system is producing a large area of cloudiness and thunderstorms. Although thunderstorm activity has continued to increase and become a little better organized since yesterday, upper-level winds are expected to be only marginally conducive for significant development of this system over the next day or two while it moves westward at around 15 mph. By late Wednesday as the wave approaches the Windward Islands, upper-level winds are forecast to become quite hostile for any further development.
The Hurricane Center is also monitoring a large low pressure system located over the far eastern tropical Atlantic Ocean, less than 300 miles southeast of the Cabo Verde Islands. This system is moving slowly west-northwestward to northwestward. Satellite imagery and surface wind data indicate that low has become better defined since yesterday, and shower and thunderstorm activityis showing increasing signs of organization. If this recent development trend continues, then a tropical depression or a tropical storm is likely to form later tonight or early Tuesday while the low moves generally northwestward toward the Cabo Verde Islands. Strong upper-level winds should prevent any further development by midweek. NHC forecasters are giving this system a 90 percent chance for development over the next 5 days.
Finally, the National Hurricane Center has issued its last advisory on post-tropical storm Melissa, located over the northwestern Atlantic, roughly 405 miles south-southeast of Cape Race, Newfoundland. The system has lost its tropical characteristics as it is moving off to the east at 23 mph.