Disturbance 90L brings heavy rain to Puerto Rico; major pollution in California
A surface low pressure system (90L) just east of Puerto Rico is moving to the west at 5-10 mph. This low is entangled with an upper-level low pressure system that is bringing about 30 knots of wind shear, so no development is likely today. Long range radar out of Puerto Rico shows bands of heavy rain hitting the islands and surrounding waters, but these bands are not well-organized. Satellite loops show most of the heavy thunderstorm activity is to the northeast of the low's center of circulation, and high wind shear is keeping this thunderstorm activity disorganized. This morning's QuikSCAT pass missed 90L.
Figure 1. Latest satellite image of 90L. Image credit: NOAA.
The surface low is expected to separate from the upper level low tonight and move west-southwest or southwest across Puerto Rico, bringing the threat of heavy rain and flooding to the island. Recent rains have left large areas of interior and western Puerto Rico at or near saturation, and mudslides were reported yesterday in Utuado. Flooding problems and mudslides are likely across Puerto Rico and the Virgin Islands Friday and Saturday, and this is shaping up to be the most significant rain event of the fall wet season thus far for Puerto Rico.
On Friday and Saturday, 90L will move westward along or just south of Hispaniola, bringing heavy rain, flash flooding, and possible mudslides to that island. The ECMWF and NOGAPS models predict that wind shear will drop to 10-20 knots by Friday night, which may allow some slow development of the disturbance if the center remains over water. The GFS model keeps wind shear 20-30 knots through the period, and does not develop 90L. By Saturday, the storm will near Jamaica, and the ECMWF and NOGAPS models predict a tropical depression will form by Sunday. Steering currents grow weak on Monday, and the storm could stall out for many days in the Western Caribbean, in an area of low wind shear and high heat content waters. This may allow the system to intensify into a hurricane. The eventual fate of this system is highly uncertain, since steering currents will be so weak. Those of you planning to travel to the Western Caribbean next week should keep a close watch on this system. NHC has not scheduled any flights into 90L yet.
It is possible that wind shear and passage over the islands will sufficiently disrupt this disturbance so that it does not develop. However, surface pressures have fallen 2-3 mb over most of the Western Caribbean the past two days, and there is a good chance that a new area of disturbed weather will develop. One such disturbance formed yesterday south of Haiti, but has since dissipated. Unsettled rainy weather can be expected to affect much of the Western Caribbean over the coming week.
California's fires
Surface maps show that the high pressure system that brought this week's strong Santa Ana winds to Southern California has now moved east and is over Colorado. The Santa Ana winds have ceased over California, and only light winds with afternoon sea breezes are expected today and for the next seven days. No precipitation is expected for at least the next week. The combination of light winds and lack of rain will make for a serious air pollution hazard in the region, until the fires are extinguished. There is still plenty of smoke over the ocean waters (Figure 2) that will get blown back over land by afternoon sea breezes over the next week.
Figure 2. Visible satellite image at 1:45 pm PDT Wednesday October 24, showing a huge area of smoke over the Pacific Ocean. Some of this smoke is being blown northward (top of image), and is expected to move over northern California and northern Nevada over next two days. This northward-moving smoke is being lifted by the flow around an approaching low pressure system, and is not expected to affect air quality near the surface. However, the smoke just offshore San Diego and Los Angeles will remain near the surface, and some of it will be pushed back over land by afternoon sea breezes. Image credit: NASA.
Jeff Masters
with all the smoke in the air the moon last night was looking like holloween.
Reader Comments
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I live just a few blocks from the NHC!
there is still a lot of uncertainty with 90L
That's an understatement.
Looking at Key West radar - looks like you're going to get wet !!
Keep us up to date Adrian - always nice to hear what's going on on the "inside"
Breath JFV breath??? please specify Floodman?
You seem tense; your posts are indicative of not taking a breath...hence, "breathe, JFV, breathe"
Thanks floodman! LOL
You're welcome, dear...and how are you today?
-------------------------------
It rained, finally. But will it help?
Recent precipitation won't end Va.'s drought
Thursday, Oct 25, 2007 - 12:09 AM Updated: 10:22 AM
By REX SPRINGSTON
TIMES-DISPATCH STAFF WRITER
Harvey Brewton, a Richmond maintenance man, walked in the downtown Richmond drizzle without a raincoat yesterday and pegged the moment perfectly.
"It's a miserable day, and it's a good day," Brewton said. "We needed the rain because of the drought."
The long-awaited rain is expected to continue into Saturday morning, forecasters say, and will partially refill struggling streams and reservoirs -- but it won't end Virginia's widespread drought.
Over the four days, much of Virginia is expected to get 2 to 3 inches of rain, and some places might get more than 4, the National Weather Service said.
"I think this is a godsend at this point, no question about it," said Bill Sammler, a meteorologist with the Weather Service in Wakefield.
Virginia hasn't had significant rain since Sept. 14. Richmond got slightly more than an inch that day.
By 11 p.m., Richmond had received just over an inch. Most of the state got at least a quarter-inch. Norfolk and parts of the Eastern Shore received about 2 inches; parts of Southside Virginia got 1 to 2 inches and part of Henry County got 4 inches, the Weather Service said.
Before the storms came, rainfall in Richmond was about 6.5 inches below normal for the year.
This rain will be particularly helpful because less moisture evaporates in the fall than during the heat of summer. Also, many trees go dormant in the fall and stop sucking water from the ground, and people water their lawns less.
All that means more water is available for parched streams, lakes and soils.
"Two inches of rain can have a much more substantial benefit this time of year than it can in July and August," Sammler said.
Still, several similar rains are needed to end the drought.
"This is good news, but we're not out of the woods yet," said Terry Wagner, chairman of the Virginia Drought Monitoring Task Force.
The rains will help shrinking reservoirs and streams build back up temporarily, Wagner said. "That graph that's been going down is apt to turn around."
Nearly all of Virginia is suffering from drought, and the rest is abnormally dry.
Parts of far Southwest Virginia are in an exceptional drought, the most-serious category. Much of central and Southside Virginia is in an extreme drought, the second-worst category.
The much-needed rain is being produced largely by a low-pressure system in the lower Mississippi Valley region. Spinning counter-clockwise, the system is drawing moist air here from the Gulf of Mexico.
Today is expected to be a dreary one in Richmond, with perhaps some drizzle and a high temperature around 60.
Heavier rains are expected tonight, tomorrow and Saturday morning. Contact Rex Springston at (804) 649-6453 or rspringston@timesdispatch.com.
I wonder if Jerry and Tommy Chong are related in any way lol
well got to go out and enjoy this weather on my way home, see you guys in about 2 hours
I know that dude, man!
I see Floodman, I apprecaite your concern though regardless.
LOL...JFV, you and I seem to be diametric opposites: you are a very formal and proper young man (do not get me wrong, that is a VERY good thing); I am a beat up old reprobate...
321. Floodman 4:56 PM EDT on October 25, 2007
Yep...how you doing, StormW?
Good!
IRT to your statement about an outlier in Nov. as far as development. Can't rule it out. We had Kate back in 1985...15-23 Nov. CAT 3...hit Fla. Panhandle.
Thank you, sir...it just seems that this is a season for odd effects; that having been said, perhaps we should see what 90L does, though...
Thanks for the compliment floodman, this means a lot to me.
You're welcome, JFV. I used to be a very formal and proper young man, but I fell in with evil company LOL
292. InTheCone 4:32 PM EDT on October 25, 2007 One way or another there will be a large helping of black clad fowl served up in many tasty variations!!!!
Between the West Nile Virus and the rate you guys dish it out I fear the poor creature will end up on the endangered species list.
Anything new with 90L?
--------------------------------------------------------------------------------
000
ABNT20 KNHC 252110
TWOAT
TROPICAL WEATHER OUTLOOK
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
530 PM EDT THU OCT 25 2007
FOR THE NORTH ATLANTIC...CARIBBEAN SEA AND THE GULF OF MEXICO...
SHOWER ACTIVITY HAS INCREASED AND SURFACE PRESSURES ARE FALLING IN
ASSOCIATION WITH THE LOW PRESSURE SYSTEM CENTERED JUST NORTHEAST OF
THE VIRGIN ISLANDS. THIS SYSTEM CONTINUES TO SHOW SIGNS OF
ORGANIZATION...AND ALTHOUGH UPPER-LEVEL WINDS ARE GENERALLY
UNFAVORABLE FOR SIGNIFICANT DEVELOPMENT...THIS SYSTEM HAS THE
POTENTIAL TO BECOME A TROPICAL DEPRESSION. A WEST-SOUTHWESTWARD
MOTION INTO THE CARIBBEAN SEA IS EXPECTED OVER THE NEXT COUPLE
DAYS...WHICH WOULD BRING SHOWERS AND GUSTY WINDS ACROSS THE U.S.
VIRGIN ISLANDS...PUERTO RICO...AND HISPANIOLA.
ELSEWHERE...TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
NEXT 48 HOURS.
$$
FORECASTER MAINELLI
This bunch here grows 'em to keep up with demand!! I have a VERY LARGE aviary on my premesis just to keep up w/ my own personal consumption - lol!!
I'm just waiting for the official WunderCrow Cookbook - :o)
314. seflagamma 3:52 PM CDT on October 25, 2007
Thanks floodman! LOL
You're welcome, dear...and how are you today?
I am busy at work and should not be on these blogs! Thanks for asking. LOL
I really got to sign off and get a couple more tasks completed.
I guess we will watch and wait; got 2 more long work days ahead of me so will be able to flip on this screen from time to time to see what is going on.
Take care everyone.
Yep - saw that coming - could be a gully washer!!
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