NATIONAL WEATHER SUMMARY

 

JULY 2010

 

1^st-10^th…Severe weather swept through the Northern Rockies on Friday, while the remnants of Alex brought rain and wind to the Southern Plains. Most of the nation saw mild weather as high pressure hovered over the Eastern half of the country, while low pressure sits over the West. The trough in the West created a front that stretched from the Northern High Plains to the Intermountain West. The system triggered scattered showers and thunderstorms, some of which have turned severe. The region did not see significant precipitation, but quarter size hail with wind gusts up to 40 mph was reported in Brady, Montana, while strong winds blew down trees and power lines in Lothair, Montana. Meanwhile in the South, the remnants of Hurricane Alex continued to track westward through northern Mexico. Flow around this system picked up moisture from the Gulf of Mexico, and spread scattered showers with strong winds over Texas and Oklahoma. Houston reported another 2.30 inches of rain on Friday and most areas of Texas saw at least an inch of rain. Strong winds with gusts up to 63 mph were reported in Corpus Christi. Also in the South, a front hovering over the northern shores of the Gulf of Mexico brought scattered storms with light rain over northern Florida. Most of the Southeast and Southern Plains remained uncomfortably warm and humid on Friday. The North remained under pleasant weather conditions as high pressure hovered over the Great Lakes and most of the Mississippi River Valley. This brought plenty of sunshine with highs in the 80s to near 90 over the Midwest and New England.

The Central Plains saw some wet weather on Monday, as a front pushed eastward throughout the day. A low pressure system moved through Canada and created a strong cold front that extended from the Great Lakes into the Central Plains. The system kicked up scattered showers and thunderstorms, but these storms have not yet turned severe. The Central Plains reported periods of heavy rain and strong winds, with 2.95 inches and gusts up to 50 mph reported in Dodge City, Kansas. Elsewhere along the front saw rainfall totals between a half of an inch to an inch. Due to this slow moving system, flooding remained a concern over the Mid-Mississippi River Valley and the low levels of the Plains. Meanwhile in the East, a strong ridge of high pressure continued to dominate most of the East Coast. This allowed for highs to reach into the 100s over parts of New England. While skies remained sunny, air quality was a concern as high pressure acts to trap pollutants near the surface. In the Southeast, scattered storms persisted on Monday as moisture continued pushing onshore from the Gulf of Mexico. Invest 95 with a low 10% chance of tropical storm development, sat 50 miles south of Louisiana. It slowly diminished as upper level winds were not favorable for storm development. However, the region saw another day with scattered showers and thunderstorms, none of which have turned severe.

A front over the Central U.S. brought another rainy day with floods to the Mississippi River Valley, while Tropical Depression Two moved into southern Texas on Thursday. An area of low pressure spinning in the Gulf of Mexico reached tropical depression strength with maximum sustained winds up to 35 mph. The system quickly moved onshore and pulled ample moisture onshore from the Gulf, which spread periods of heavy rainfall over the Southern Plains. These areas saw periods of heavy rain with 2.38 inches reported in Tulsa Jones, Oklahoma, while much of southern Texas saw at least an inch of rain. To the north, a strong frontal boundary continued tracking southeastward through the Central U.S. The system brought another round of scattered showers and thunderstorms, but none of which have turned severe yet. Most of the Midwest and Great Lakes saw highs in the 80s, which allowed for another hot and humid day. In the East, a ridge of high pressure continued to hover over the East Coast. This allowed for another hot and dry day as highs reached into the 90s. The region remained under heat and air quality advisories, as high pressure keeps heat and pollution near the surface. Elsewhere, the West Coast remained under sunny skies and dry conditions as a ridge of high pressure dominated the weather on Thursday. Cool and breezy conditions persisted along the coasts, while the deserts reached into the 100s.

The Eastern U.S. saw a rainy day on Friday, as a cold front slowly moved through the country. A low pressure system continued to track through Canada and created a cold front that extended from the Northeast, down the Ohio River Valley, and into the Lower Mississippi and Southern Plains. The system kicked up scattered showers and thunderstorms throughout the day, but have not yet turned severe. Flooding remained an issue along the front because this slow-moving system has poured over the Mid-Mississippi River for the past few days. Springfield, Ohio reported 1.25 inches of rain, while Jamestown, New York saw 1.12 inches of rain. In the South, the front gained energy from the remnants of Tropical Depression Two that continued to move westward along the Texas and Mexico border. The system helped pull moisture onshore from the Gulf of Mexico, and allowed for periods of heavy rainfall to persist. Wichita Falls, Texas reported 2.03 inches of rain with. Strong winds with gusts up to 40 mph were also reported in multiple areas of Texas.

Elsewhere, the Northern and Central Plains, as well as the Upper Midwest saw a few patchy clouds with mostly sunny skies as a ridge of high pressure continued to build in. This allowed for another pleasant day with highs in the 80s over most of the region.

In the West, patchy clouds developed over the Southwest as moisture pushed in from the Gulf of Mexico. Otherwise, the rest of the West Coast remained mostly sunny under a strong ridge of high pressure. Onshore flow along the coasts brought low clouds and cool conditions.

 

11^th-17^th…The Eastern U.S. saw active weather on Monday, as front hovered over the East Coast. A low pressure system moved over the Great Lakes, while a smaller trough hovered over New England. These systems created a warm front that moved up the coast, pulled moisture in from the Atlantic Ocean, and kicked up scattered showers and thunderstorms. Some of these storms have turned severe. Strong winds blew down trees and power lines in Newton New Hampshire and Huntersville, North Carolina. Hail was also reported in Newton, New Hampshire. Periods of heavy rainfall was associated with this system. In Memphis, Tennessee, 3.76 inches of rain was reported, while 2.25 inches was reported in Fairborn, Ohio early Monday morning. A cold front followed this system through the Midwest and Mid-Mississippi River Valley. This allowed for scattered showers to develop, with rainfall totals ranging around an inch, and severe weather has not yet been reported. Ankeny, Iowa reported 1.16 inches of rain.

Behind this system in the Plains, another front developed as a low pressure system moved off the Central Rockies. This created a small warm front that moved northward through the Southern Plains. Severe weather has not yet developed, but periods of heavy rainfall hit parts of Oklahoma and Texas, due to ample moisture from the Gulf of Mexico feeding strength into this system. In Lawton, Oklahoma, 0.85 inches of rain has been reported.

Out West saw a mild weather day, as high pressure hovered over the West Coast. Mostly sunny skies prevailed in California and the Southwest, while a mild trough of low pressure in the north pushed overcast skies into the Pacific Northwest. Precipitation has not yet developed over the region.

 

Unsettling weather activity developed in the Upper Midwest on Wednesday as a low pressure system hung over southeastern Saskatchewan, Canada. Waves of low pressure and a cold front associated with this main low extended across the eastern Northern Plains and the Upper Mississippi Valley through the Central Plains and into the Four Corners. Meanwhile, an associated warm front stretched from the Upper Mississippi Valley through the western Ohio Valley into the western Tennessee Valley. Increasing instability associated with these disturbances combined with daytime heating and moisture to produce areas of scattered showers and thunderstorms with periods of heavy rainfall along and near the fronts in Minnesota and northern Wisconsin. Storms in these regions had a moderate chance of turning severe with large hail, damaging winds, and tornadoes. As of this afternoon, numerous high wind reports and several instances of penny to golf ball sized hail (1.00 - 1.75 inches) were reported in central Minnesota and northwestern Wisconsin. Scattered showers and less intense thunderstorms also developed along other portions of the associated cold front in the Central Plains. Storms from the Upper Great Lakes through the Central Plains had a slight chance of turning severe.

 

Elsewhere, hot temperatures and high humidity levels forced heat index values to push past the century mark in the Central US. Hot weather conditions also persisted across the Southwest, while a more gradual warm-up continued across the West Coast states.

In the East, scattered thunderstorms with periods of locally heavy rainfall continued to fire up throughout portions of New England as waves of low pressure developed along a cold front that cleared the Northeast Coast. Additional showers and thunderstorms developed in the Mid-Atlantic and the Southeast near the tail of this cold front.

Wet weather persisted in the East, while the West remained hot on Friday. A low pressure system continued moving through Canada, just north of the Great Lakes. This system created a front that tracked from the Great Lakes and Midwest, into the Northeast. This front stretched southward over New England, down the Tennessee Valley, and into the Southeast. Scattered showers and thunderstorms developed along this front as it obtained moisture from the Atlantic Ocean and the Gulf of Mexico. Warm and humid conditions across the Southeast allowed for these storms to turn severe with heavy rainfall, hail, and damaging winds. Pompano Beach, Florida saw 1.31 inches of rain associated with strong thunderstorms early Friday morning. Mobile, Alabama saw 0.92 inches of rain, while trees were blown down in multiple areas across Mississippi and Alabama. Quarter size hail was reported just south of Vernon, Alabama. The northern end of this front also brought wet weather with rainfall totals near a half of an inch. Behind this system in the Plains, a ridge of high pressure quickly built in as the low and associated front passed to the East. This brought warm and sunny weather to the Midwest and Plains. Most of the Central US saw highs in the 90s on Friday. Further west, patchy clouds developed over the deserts of the Southwest. A high pressure system allowed for hot conditions, while moisture trapped underneath the ridge produced scattered clouds. This led to the development of high-level scattered showers and thunderstorms over Nevada, Arizona, southern California, and New Mexico. Meanwhile, the rest of the West Coast saw sunny skies and warm conditions, as the ridge of high pressure pushed moisture offshore.

 

18^th-24^th…Areas of active weather developed across the nation on Wednesday as disturbances from the Northeast through the Northern Rockies increased instability through the afternoon.

In the East, cyclonic flow associated with a low pressure system in southeastern Canada spread across the Northeast and sparked bands of showers and thunderstorms across New England. Meanwhile, clusters of thunderstorms and possible severe weather activity developed from the Mid-Atlantic and Carolinas through the Central Plains.

In the West, southwest monsoon moisture spread across the Four Corners and triggered scattered clouds with a few isolated thunderstorms in the Southwest. Additional, showers and thunderstorms developed to the north along a nearly stationary frontal boundary that reached through southeastern Idaho, southern Wyoming and eastward into the Central Plains. A low pressure trough that moved into the Pacific Northwest enhanced thunderstorm activity throughout these regions. Storms in the Northern Rockies and Northern Plains had a slight chance of turning severe with damaging wind and hail.

Tropical Storm Bonnie moved into the Gulf of Mexico on Friday and brought storms to Florida. The system remained relatively unorganized at tropical storm strength with maximum sustained winds at 40 mph. The entire western coast of Florida has been placed under a tropical storm warming as the system approached and brought heavy rain and strong winds. Kendall, Florida saw 2.36 inches of rain, while Miami reported 1.50 inches. Elsewhere across the South, heat advisories remained in effect and stretched from the Gulf up the Mississippi River to the Ohio River Valley and extended eastward to the East Coast. Extremely hot temperatures resulted from a large ridge of high pressure hovering over the Southeastern US. This brought plenty of sunshine allowing for highs to reach into the mid-90s. However, moist air that moved in from the Gulf allowed for humid conditions, which pushed heat indices well above 100 degrees.

Meanwhile in the North, scattered showers persisted across the Northwest as a front lingered over the region. This brought periods of heavy rain but storms have not turned severe. In the Northern Plains, another low pressure system developed as it moved off the Rockies and created another front that moved through the Northern Plains and Upper Midwest. Severe storms popped up along this front with reports of hail in Bowman, North Dakota and strong wind gusts up to 70 mph associated with thunderstorms in Scranton, North Dakota. Behind this system in the West, a ridge of high pressure covered the West Coast and brought sunny skies and hot conditions with lingering clouds along the coasts. However, monsoon storms persisted over the deserts of the Southwest. Dry surface conditions allowed for most precipitation to evaporate before hitting the surface, thus, most areas saw around a quarter of an inch of rain.

Plenty of active weather developed in the eastern half of the nation on Wednesday. A cold front associated with a low pressure system in eastern Canada reached across the Upper Great Lakes and extended southwestward through the Central Plains in the afternoon. Ahead of the cold front, hot and humid weather developed throughout the western Ohio Valley with daytime highs reaching well into the 90s and heat indices pushing past 100 degrees. Muggy conditions and increased instability from southern Michigan through Kentucky fueled scattered showers and thunderstorms through the afternoon. Some of these storms, from the Lower Great Lakes through areas of the northern Ohio Valley, had the potential to turn severe.

 

Elsewhere in the East, scattered showers and thunderstorms developed over portions of the Southeast. Rich tropical moisture also spread across the Texas coast and kicked up scattered to numerous showers and thunderstorms with potentially heavy downpours in southeastern Texas.

In the West, waves of energy in the Northwest produced areas of isolated to scattered showers and thunderstorms in the Northern High Plains. To the south, monsoon moisture over the Southwest and portions of the Central and Southern Rockies aided in producing daytime showers and thunderstorms.

Scattered storms developed in the Midwest on Friday as a low pressure system pushed a front from the Northern and Central Plains into the Upper Mississippi River Valley. The system obtained moisture from high pressure in the Gulf of Mexico pushing warm and moist air into the Central US. Thus, scattered showers and thunderstorms developed along the warm front. Storms have not yet turned severe but periods of heavy rains swept through the Dakotas and Upper Midwest. Rainfall totals varied between 1-1.5 inches, while Sioux Falls, South Dakota reported 2.41 inches associated with strong thunderstorms. Thus, floods continued to threaten much of Iowa, Minnesota, and Illinois, as these storms strengthened throughout the day. In the East, a cold front pushed offshore and into the Atlantic Ocean. This allowed for a ridge of high pressure to build in and dry out the region. Most areas of the Northeast and New England saw sunny skies with highs ranging in the 80s, thus, slightly more comfortable conditions than earlier this week. The South, however, saw another hot and humid day with highs ranging in the 90s and 100s. Heat indices remain in effect over the Gulf and mid-Atlantic states because humid conditions allowed for heat indices to reach between 110 and 120. Out West, monsoonal moisture lingered over the Southwest and continued to kick up scattered high-level showers and thunderstorms. However, dry conditions allowed for most of the precipitation to evaporate before it hit the surface. The rest of the West Coast remained sunny and warm, with cool and cloudy conditions along the coast.

 

Jim G. Munley, jr.
http://www.jimmunleywx.com