More Rain Tonight?

The tropical wave is now over Texas. It is a disorganized system, so it is hard to predict where the rain will be tonight. Let’s look at High-Resolution Rapid Refresh (HRRR), North American Mesoscale Forecast System (NAM), Regional Model (RGEM), and Weather Research and Forecast (WRF-ARW, and WRF-NMM). They are at 0900Z or 4:00 AM CDT.

The HRRR has heavy rain mostly west and southwest of Houston. The NAM has heavy rain over Matagorda Bay and east of Houston. The RGEM has an axis of heavy rain from Corpus Christi area to East Texas. The WRF-ARW has the heavy rain over Matagorda Bay. The WRF-NMM has heavy rain south of San Antonio. This shows that forecasting where heavy rain will fall tonight is all over the place with this tropical wave.

Looking at the most recent Doppler radar mosaic, there is heavy rain over East Texas and Southwest Louisiana. It is not really active right now.

However, with tropical moisture, thunderstorms tend to form at night, especially near the center of the low pressure system. They are called core rains and they can dump heavy rain in a short time. Harvey, Allison, Claudette, and Thrall 1921 Flood were core rain events as flooding rain fell at night. This system is disorganized, so it will be hard to tell where it will exactly form. Some forecast models want the heavy rain over Matagorda Bay, while some have it over Southeast Texas.

Many are wondering what is the forecasted rain amount. The rainfall forecast models are from GFS, Canadian, EURO, ICON, and Weather Prediction Center (WPC). They are all 7 day rainfall total forecast.

The GFS has 4 inches of rain over Galveston Bay. The area of heaviest rain is east of Houston.

The Canadian has nearly 11 inches of rain just north of Houston. The largest area of heavy rain is north of Houston.

The EURO has backed down on nearly 30 inches of rain. It has nearly 15 inches of rain south of San Antonio. There is a large area of heavy rain southwest of Houston.

The ICON has over 13 inches of rain near Aransas Pass. There is an area of 8 inches of rain west of Houston. Most of the heavy rain is over the Gulf Of Mexico.

The WPC has 10 inches of rain over an Matagorda Bay and Victoria. Houston area has 5 to 7 inches of rain.

The rainfall forecast is all over the place on where it will fall and even the amount. This is a very frustrating forecast. Regardless of forecast models, all forecast heavy rain will fall somewhere.

Here is what I think will happen.
-Someone will see heavy rain tonight.
-Not ruling out Houston area getting heavy rain tonight.
-Rainfall amounts could range from 5 to 10 inches of rain with isolated totals approaching and exceeding 15 inches.

The forecast models came from Weather.US, Tropical Tidbits, National Hurricane Center, and National Weather Service. Special thanks to all of them.

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Invest 91L As This Weekend’s Rainmaker?

Invest 91L is over the Gulf of Mexico. Currently on satellite from CIMSS-Tropical Cyclones, it does not look too impressive.

Of course with tropical lows, they tend to fire up at night as they are warmer than the surrounding area. I would not be surprised to see a lot of thunderstorms come morning. As the time passes, where does Invest 91L go?

Most forecast models have it going towards South Texas or Mexico. There is a chance that it could go over Southeast Texas. If it goes into Mexico or South Texas, there is better chance for rain since the northeast side is the wettest as it is the “dirty” side of the tropical low. The intensity forecast models are split.

Some have Invest 91L as a tropical wave. Some have it intensifying into a tropical depression. Some have it becoming a tropical storm. If it becomes a tropical storm, it would be Beryl. Like I say, intensity forecast is not really reliable. At this point, I would be more concerned with the rain than some tropical storm developing.

Various forecast models have different rain amounts, which are from GFS, Canadian, EURO, and Weather Prediction Center (WPC). They are from Weather.US and Weather Prediction Center (WPC)-Quantitative Precipitation Forecasts (QPF). These are 7 day rainfall totals.

The GFS has the heaviest rain over Houston area. It forecasts up to 8 inches of rain. A large area of Southeast Texas has 3 to 6 inches of rain.

The Canadian forecasts rain amounts of up to 6 inches over Austin area and around Halletsville.

The EURO forcasts up to 20 inches of rain southeast of San Antonio. There is 10 inches south of Houston. The EURO is the wettest of the forecast models.

The WPC has up to 5 inches of rain over Southeast Texas. It is the driest of the forecast models.

All the forecast models have rain for Texas. The only difference is the amount. Some are very bullish, while others are not. The plus side is that it will put a dent on the drought in Texas.

Most areas in Texas are in a drought. The rains can alleviate the drought, which is a good thing. This also increases the risk for flooding, which is not good almost a year after Harvey ravaged Texas with epic rainfall.

I think Invest 91L will be more of a rain event this weekend. Tropical development is not likely, but cannot be ruled out. Regardless, Invest 91L needs to be watched as it could be more of a rain event that may cause flooding in some areas.

The forecast models came from NCAR-Tropical Cyclone Guidance. The GIS drought map is from United States Drought Monitor.

A Weakening Bud And Invest 91L

Oh how the mighty have fallen! Yesterday, Bud was a hurricane. Today it is a tropical storm with 50 mph 44 knots 80 km/h winds. It was once a formidable Category 3 hurricane. All the forecast models have Bud weakening.

With Bud running into cooler water and closer to land, it is most likely to weaken. The next important question is where Bud goes.

The forecast models are having Bud moving towards Baja California and the Southwestern US as a low pressure system. The moisture from Bud is certainly welcomed in the Southwest as they are very dry.

Almost the entire Four Corners is engulfed in a severe drought. It centers around where the Four Corners meet. There is also a severe drought in the Texas Panhandle region. Any rain is welcomed regardless. This leads to Invest 91L in the Caribbean. Many are asking where 91L will go.

Most of the forecast models have Invest 91L heading towards either Mexico or Deep South Texas. Some have it heading towards Southeast Texas. Regardless of where 91L goes, rain will be the main issue. Since Invest 91L is over an area of warm water, does it have a chance of developing?

Most forecast models have 91L at tropical wave or tropical depression. One has it as a tropical storm. Again, it is too early to tell if it will develop. Tropical waves or low pressure areas in the Caribbean and Gulf of Mexico can form suddenly into a tropical storm or even hurricane. It has happened many times in the past. I am not suggesting it will happen with 91L. It is something to consider.

The Tropical Cyclone Formation Probability Guidance Product does give Invest 91L a chance of developing into a tropical cyclone in the next 48 hours. Again, that is only a small chance of developing.

Since, we are on the topic of tropical weather trouble, it brings rain. Various forecast models have different rain amounts, which are from GFS, Canadian, EURO, and Weather Prediction Center (WPC). They are from Weather.US and Weather Prediction Center (WPC)-Quantitative Precipitation Forecasts (QPF). These are 7 day rainfall totals.

The GFS has less rain for Texas and the Southwest. Southeast Texas has 2 to 4 inches of rain. The Southwest sees 0.50 to 2 inches of rain with 6 inches in the mountains.

The Canadian is not particularly generous for the Southwest. However for Southeast, Texas it has up to 8 inches of rain.

The EURO is generous for Southwest and Texas. The mountains of Arizona, New Mexico, and Colorado have up 8 inches of rain. Most of Arizona is wet as well compared to GFS and Canadian.

The WPC has 2 to 4 inches of rain over Southeast Texas. The Southwest has 0.50 to 1 inches of rain with isolated areas seeing 2 inches of rain.

The forecast models are unanimous on that rain will fall in Texas and the Southwest. They diverge on rain amount. Some forecast lesser amounts, while others forecast higher amounts. We should have a better idea of rain amounts later on.

My take on this. Invest 91L is more likely going to be a rain event. I do not expect 91L will develop at this point, but of course anything can happen. I do not think we will see another Harvey event from 91L. It is not forecasted to linger over Texas, like what Harvey or Allison did. As for Bud, the Southwestern US should welcome the rain with open arms. They will need it for sure.

The forecast models came from NCAR-Tropical Cyclone Guidance. The GIS drought map is from United States Drought Monitor.

Hurricane Bud And Invest 91L

NOAA/NESDIS/STAR GOES-16 ABI BAND 11 OR_ABI-L1b-RadF-M3C11_G16_s20181640230401_e20181640241168_c20181640241232.nc

It is June and the tropics are heating up. We have two areas of interests, Hurricane Bud in the East Pacific and Invest 91L in the Caribbean. Let’s start with Bud.

Hurricane Bud was a powerful Category 3 hurricane that weakened into a Category 2 hurricane with 100 mph 85 knots 161 km/h winds. It is due to cooler water Bud is encountering. Cooler water tends to weaken hurricanes even if there is not a whole of wind shear.

The area of warm water in the East Pacific is not that great. However, two major hurricanes have formed so far, which are Aletta and Bud. East Pacific is one of the most active basins despite its small size. As Bud weakens, where does it go? Here is a heat map forecast for Bud.

Most forecast models have Bud heading towards Baja California later by the end of the week. Where it goes after looks to be heading towards the Southwest. They can certainly use the rainfall as they are in a severe drought. The next question is how strong will Bud be?

Most forecast models have Bud as a tropical storm with one as a Category 1 hurricane around the time it us close to Baja California. From there, it is forecasted to weaken to a tropical depression.

The next problem is closer to home, Invest 91L. It is located off the coast of Honduras in the Caribbean. It is right now just a tropical wave with a cluster of thunderstorms. Many are wondering where will 91L will go? Here is a heat map forecast for 91L.

Most of the forecast models have 91L heading towards the Western Gulf of Mexico. One has it heading towards Florida looping around. It is just one forecast model. The forecast models at this time are heading towards Texas. Since this is a tropical wave, the forecast model is subject to change. The $64,000 question is will 91L become a tropical storm or hurricane, which would be Beryl.

Most forecast models keep 91L at tropical depression. Only one has a tropical storm at this time. Intensity forecast models are unreliable, especially if nothing has developed yet. Some factors do favor development. Let’s look at the water around Invest 91L.

The depth of warm water in Caribbean and Gulf of Mexico is great and over a large area. The heat potential is fairly high in the Gulf of Mexico and Caribbean. Warm water is certainly a factor in tropical development, but not the only one.

Wind shear over the Gulf of Mexico is within average and looks to be trending downward. Less wind shear is more favorable for tropical development. If there is strong wind shear over warm water, tropical development is greatly reduced as they blow tops of thunderstorm clouds that forming into something tropical.

At this time, I do not think Invest 91L will develop. It looks to be more of a rainmaker. However, anything can change between now and the end of the week.

The forecast models came from NCAR-Tropical Cyclone Guidance. The tropical heat came from A href=http://www.aoml.noaa.gov/phod/cyclone/data/go.html>Tropical Cyclone Heat Potential (TCHP). Wind shear map came from Tropical Cyclone Formation Probability Guidance Product.

2017-2018 Winter Forecast

Winter has started and Christmas has passed. It is very cold throughout America. Last winter we had a borderline Neutral/La Nina. This time around, we have La Nina. Other factors to consider are Pacific Decadal Oscillation (PDO), Atlantic Multidecadal Oscillation (AMO), Northeast Pacific Warm Pool (NEPWP), Equatorial Indian Ocean (EIOI), Indian Ocean Dipole (IOD), Tropical South Atlantic (TSAI), Roaring Forties (R40I), Hudson and Baffin Bay (HBB), and Quasi-Biennial Oscillation (QBO). However, since this El Nino is large and strong and has significant impact, it will weigh in more than other factors listed. Here are the analog winters I came up with.

1881-1882
1928-1929
1933-1934
1937-1938
1944-1945
1949-1950
1961-1962
1984-1985
2000-2001

I chose these winters because the previous winter was La Nina or Neutral. Here is a table I created to identify strongest analogs.

Year AMO PDO NEPWP EIOI IOD TSAI R40I HBB QBO Total
1881-1882     1 1 1   1     4
1928-1929 1 1     1     1   4
1933-1934 1 1 1 3
1937-1938 1 1 2
1944-1945 1 1 1 1   1 1 1   7
1949-1950 1 1 1   1 1     1 6
1961-1962 1 1 1     1 1     5
1984-1985       1 1 1 1   1 5
2000-2001 1 1 1 1 1 1 1   1 8

I look at eight ocean and one upper wind patterns based on Fall (September to November) averages. The cutoff for further analysis is four (before 1948 due to QBO data not available). With QBO, the cutoff is five. We can eliminate these winters.
1933-1934
1937-1938

The analogs I will be looking at are:
1881-1882
1928-1929
1944-1945
1949-1950
1961-1962
1984-1985
2000-2001

Let’s start with the ever important temperature. All maps were generated with 20th Century Reanalysis Monthly Composites. They are all Northern Hemisphere.

Alaska, Bering Sea, Southern US, Eastern US, Eastern Canada, Greenland, and Western China are warmer than normal. Arctic, Siberia, Korea, Japan, Central Asia, Southeast Asia, Europe, North Africa, Western US, and Western Canada are cooler than normal. Southeast Texas is warmer. Keep in mind, some areas do not have weather records, so this may be spurious as it includes 1881-1882.

Wonder what winter will be like in the rain department?

It is drier in Western US, Western Canada, Southeast US, Cuba, Bahamas, Southern China, Central Asia, Western Europe, and Northern Europe. It is wetter in Central US, Caribbean, Alaska, Northern Japan, Southeast Asia, and North Africa. Southeast Texas sees average amount of rain in the winter. Again, this may be spurious as it includes 1881-1882.

Let’s look at the upper air pattern.

There is upper level ridging south of Alaska, which is negative East Pacific Oscillation (EPO), Eastern US, Siberia, Greenland, and Northeast Canada. Ridging over Greenland and Northeast Canada is negative North Atlantic Oscillation (NAO). There is troughing over Central Canada and one running from Japan, Korea, and to all of Central Asia. Negative NAO and EPO usually means cold air will go down south.

How were winters like in these analog years?

1881-1882
A warm winter dominated the US. Southeast Texas had a warm winter.

1928-1929
A cold blast came on the start of 1929 in Southeast Texas. Another hard freeze came in February 1929. It did not go above freezing on February 9, 1929 with high of 29°F.

1944-1945
A world engulfed in World War II. No freezes occurred in Southeast Texas.

1949-1950
Most of the US had a warm winter, including Southeast Texas.

1961-1962
Snow fell in Houston area in December 1961. January 1962 had a strong cold blast in America. A strong high pressure with pressure of 1062 millibars was recorded. Many areas saw record lows set. Houston saw a record low on January 10, 1962, which has been beaten in 1977.

1984-1985
Cold blasts occurred in January and February 1985. The 1985 Presidential Inauguration was the coldest on record. Many areas saw record lows set. Houston saw record lows on January 20-21, 1985. Near records occurred on February 1-2, 1985. Snow fell in Houston in January and February 1985. San Antonio saw record snowfall on January 11-13, 1985.

2000-2001
Eastern US had a cooler than normal winter. Southeast Texas had a cold winter.

I am not suggesting we will see a cold blast on par with February 1929, January 1962, January 1985, and February 1985. It is possible this winter could see more cold blasts.

I think this winter could be a cooler winter despite what the past analog winters being warm. I would not be surprised to hear of a major cold blast this coming winter or snow falls again.

Double Trouble!

The Natonal Hurricane Center (NHC) has confirmed that Hurricane Maria made landfall as a formidable Category 5 hurricane with 160 mph 256 km/h 139 knots wind. Gusts can go as high as 240 mph 384 km/h 209 knots! It has a central pressure 924 millibars. Maria is the second Category 5 hurricane of 2017 for the Atlantic. The last time there were more than one Category 5 hurricane was in 2007 with Dean and Felix. 2005 had four Category 5 hurricanes; Emily, Katrina, Rita, and Wilma. This is going to be a very long night for the people of Dominica. I cannot imagine what it is like to be under a Category 5 monster. Strong and howling winds and buildings getting destroyed.

The hurricane force winds is going to engulf most if not all of Dominica.

Hurricane force winds are up to 58 miles 93 km 50 nautical miles across from northwest to northeast quadrant. It is moving at 9 mph 14 km/h 7.8 knots, which means they will have to endure hurricane force winds for about 6 hours! That is a very prolonged, which increases chance for great carnage in Dominica. At that speed, Hurricane Maria will dump between 8 to 12 inches/20.3 to 30.5 centimeters of rain. Some areas could see as much as 20 inches/50.8 centimeters of rain.

The big question is where the Maria go after ravaging Dominica. This is the latest heat map from various forecast models and GFS ensemble track guidance for Maria. The GFS goes up to 10 days.

Once Maria passes Dominica, Maria may go over St. Kitts, Nevis, Montserrat, U.S. Virgin Islands, British Virgin Islands, and Puerto Rico. Those areas have been ravaged by Hurricane Irma. They do not need another monster hurricane ravaging them again. Some of the forecast models put it over Puerto Rico sometimes by this Wednesday. If Maria goes over Puerto Rico, it would be a very bad disaster for the island, which is mired in a financial crisis. That will make things much worse than it is. After Puerto Rico, most forecast models have Maria going northwestward. Some have it going to the Bahamas. At this point, Maria should not be a threat to the Gulf of Mexico. That can change of course. Not something we need after Harvey and Irma. The next question is how strong will Maria be.

Most forecast models show Maria weakening to Category 4 within 36 hours. Intensity forecast is notoriously difficult. It is possible Maria could be a Category 5 hurricane by the time it hits Puerto Rico. That will make things much worse as it is. Most forecast model a weakening trend as it turns northwest. The waters north of Puerto Rico are cooler due to Hurricane Irma.

Hurricane Irma became a Category 5 in warm waters, not the warmest. The warmest waters are in the Western Caribbean between Cuba, Central America, and Yucatan Peninsula. If Maria went over that water, it would probably be more intense than Wilma in 2005.

Another hurricane I am watching is Jose. It is off the Eastern Seaboard of America. Where it goes is rather complicated. This also complicates on where Hurricane Maria ultimately goes. This is the latest heat map from various forecast models and GFS ensemble track guidance for Jose. The GFS goes up to 10 days.

The forecast models are all over where Hurricane Jose goes. Looks like Jose is likely to linger over the Atlantic. Some have it going towards Florida or New Jersey. The heat map suggests this is a low confidence forecast. Since Jose is at a more northern latitude away from the tropics, it has gotten larger as energy is spread out more.

Hurricane force winds are up to 115 miles 184 km 100 nautical miles across from northwest to northeast quadrant. There is no hurricane force winds on the southern half of Jose. Tropical storm force winds are up to 449 miles 718 km 390 nautical miles from northeast to southeast quadrant. This a lop sided hurricane. Here is the most recent intensity forecast for Jose.

Most forecast models have Jose weakening into a tropical storm in the next five days. Jose will likely become extratropical in the several days. Hurricane Jose does not look like a hurricane from satellite.

Looks more like an extratropical storm than a hurricane to me.

Here is what I think will happen.
-Maria could pose a major threat to Puerto Rico.
-Jose is likely to linger over the Atlantic.

The forecast models came from NCAR-Tropical Cyclone Guidance, NOAA Tropical Cyclone Imagery – Storm Floaters, National Hurricane Center, Tropical Cyclone Heat Potential, and Meteo-France. Special thanks to all of them.

Irma Ravages Florida Part 2

The National Hurricane Center (NHC) has Hurricane Irma is near Tampa and it is a Category 2 hurricane with 100 mph 160 km/h 87 knot winds, which is on land 85 mph 136 km/h 74 knots. Gusts are as high as 128 mph 205 km/h 111 knots. Hurricane force winds are up to 150 miles 240 km 130 nautical miles across from northeast to southeast quadrant. Tropical force winds are up to 690 miles 1,104 km 600 nautical miles across from northwest to northeast quadrant. It is a large hurricane!

Tropical storm force winds are engulfing a large portion of Florida. It is even felt in Georgia and South Carolina! That is how large Irma is. Irma got large because it is over land, which disrupts the core. There is also a cold front. Those two make Irma larger as energy is spread out. The same reason why Ike got larger before making landfall on Texas in 2008.

Irma continues to get closer to Tampa. Here is the forecast model of where Irma will go. This is the latest heat map from various forecast models and GFS ensemble track guidance for Irma. The GFS goes up to 10 days.

Interesting to note there is not much of a consensus of where Irma will go. Interestingly, there appears to be some cluster where Irma will go in the next five days. Looks like Irma may end up over Tennessee, Kentucky, Mississippi, Alabama, Arkansas, Indiana, and Illinois.

Here is what I think will happen.
-Tampa Bay Area will be ravaged by Irma.
-Storm surge and strong winds will be the main issue.
-Flooding from storm surge and heavy rain will be widespread.

The forecast models came from NCAR-Tropical Cyclone Guidance and National Hurricane Center, . Special thanks to all of them.