Monday, April 23, 2018

Weather Discussion for Monday April 23, 2018

Normal high and low temperatures for April 23-April 30  (high/low) Redding 75/50, Chico 75/47, Quincy 67/34, Chester 61/30, Susanville 64/35, Grass Valley 66/42, Weaverville 70/36, Mt. Shasta 62/ 36, Yreka 67/36, Alturas 63/31

This blog will be issued every Monday, Wednesday, and Saturday morning and updated if the weather is changing or critical or interesting weather events are occurring.

High pressure continues over the west coast.  Today through Wednesday we will see mostly sunny skies with above normal temperatures. 

In the Saturday blog I discussed the formation of a closed or cutoff low.   This morning's satellite picture (below) shows a frontal system out in the Pacific that is stretched north to south.   The low will form on southern end of this front and the drift slowly eastward.   This low will be nearing the coast by Friday and over the north state Saturday and Sunday (see map below).  Thursday we will see afternoon clouds with showers and thunderstorms over the mountains.  Friday through the weekend we will see partly cloudy skies with scattered showers and thunderstorms mainly over the foothills and mountains but with isolated activity possible in the valley.  Temperatures will cool to below normal by Friday and remain there through the weekend.

Skies clear out and temperatures return to normal Monday and Tuesday.

The Old Forecaster

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Saturday, April 21, 2018

Weather Discussion for Saturday April 21, 2018

Normal high and low temperatures for April 16-April 23  (high/low) Redding 72/48, Chico 74/45, Quincy 66/33, Chester 59/29, Susanville 63/34, Grass Valley 63/40, Weaverville 68/35, Mt. Shasta 60/ 35, Yreka 65/35, Alturas 62/30

This blog will be issued every Monday, Wednesday, and Saturday morning and updated if the weather is changing or critical or interesting weather events are occurring.

High pressure is along and over the west coast and will hold there through midweek.  During this time Northern California will be mostly sunny with some afternoon cumulus clouds over the mountains.  Temperatures will be 6 to 12 degrees above normal and winds will be light.  

A "cutoff" or "closed" low pressure system is one that forms when a portion of a low pressure trough cuts off from the main jetstream and sinks southward.  These are common during the spring and summer.  Without the jetstream or strong steering winds these lows tend to move slowly and erratically.   A cutoff low will be off the coast by late Wednesday and over the next several days will progress slowly eastward (see map below).  The low does 2 main things...first it destabilizes the atmosphere as it approaches the coast and second the southerly flow ahead of it will sometimes pull sub tropical moisture northward.  

Wednesday we will see the afternoon cumulus clouds begin to increase.  Thursday and Friday there will afternoon and evening thunderstorms over the mountains with temperatures cooling to near normal.  Saturday and Sunday the low will be close to or over the north state and there will be  thunderstorms over the foothills and mountains with isolated activity in the valley. 

The Old Forecaster

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Wednesday, April 18, 2018

Weather Discussion for Wednesday April 18, 2018

Normal high and low temperatures for April 16-April 23  (high/low) Redding 72/48, Chico 74/45, Quincy 66/33, Chester 59/29, Susanville 63/34, Grass Valley 63/40, Weaverville 68/35, Mt. Shasta 60/ 35, Yreka 65/35, Alturas 62/30

This blog will be issued every Monday, Wednesday, and Saturday morning and updated if the weather is changing or critical or interesting weather events are occurring.

A low pressure area is off the coast and is moving southeastward.   This system will move inland over Central California later today and tonight.  Northern California will have a few light showers mainly over the foothills and mountains with isolated showers in the valley.  Snow levels will be 5000 feet.  The showers will end tonight with clearing skies early Thursday.  

Thursday afternoon through the mid part of next week high pressure will be along the west coast (see map below).   The north state will be mostly sunny with temperatures running 6 to 12 degrees above normal by the weekend.  Gusty north winds are expected Thursday and Friday. 

It looks like a closed or cutoff low pressure area will develop off the coast late next week.   This would increase the chance of showers and thunderstorms. 

The Old Forecaster

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Monday, April 16, 2018

Weather Discussion for Monday April 16, 2018

Normal high and low temperatures for April 16-April 23  (high/low) Redding 72/48, Chico 74/45, Quincy 66/33, Chester 59/29, Susanville 63/34, Grass Valley 63/40, Weaverville 68/35, Mt. Shasta 60/ 35, Yreka 65/35, Alturas 62/30

This blog will be issued every Monday, Wednesday, and Saturday morning and updated if the weather is changing or critical or interesting weather events are occurring.

A cold low pressure area is just off our coast and is moving eastward.  This system will move across the area today with showers and thunderstorms.  Because the airmass is so cold hail will associated with some of the thunderstorms.  Snow levels will be 2000 to 2500 feet.

One of the critical weather issues with this low is how fast it gets east of our area and how fast the skies clear tonight.   This system will bring in very cold air tonight and with clear skies and light winds the temperatures will drop.  Some low lying wind sheltered areas in the valley may be near freezing tonight.  Better cover those tomato plants just to be safe.

Tuesday we have partly to mostly sunny skies with below normal temperatures.  Wednesday a weak low pressure area will move across Northern California .  This system will bring light showers to the foothills and mountains with a few sprinkles in the valley.  Snow levels will be near 5000 feet.

Thursday high pressure begins to build along the coast and will hold there through the weekend.  Skies will be mostly clear and temperatures will be above normal by Friday.

The Old Forecaster

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Saturday, April 14, 2018

Weather Discussion for Saturday April 14, 2018

Normal high and low temperatures for April 9-April 16  (high/low) Redding 71/46, Chico 72/45, Quincy 64/32, Chester 57/29, Susanville 62/32, Grass Valley 62/39, Weaverville 67/34, Mt. Shasta 59/ 33, Yreka 63/34, Alturas 60/28

This blog will be issued every Monday, Wednesday, and Saturday morning and updated if the weather is changing or critical or interesting weather events are occurring.

Nice weather today with sunny skies...above normal temperatures and light winds.   However, this morning's satellite picture (below) shows the next low pressure area and frontal system in the Gulf of Alaska moving slowly southeastward.   This system will spread rain over the area Sunday with scattered showers and possible thunderstorms Monday.  Snow levels will drop to 5000 feet by Sunday afternoon and on Monday in some of the showers the snow levels will be 3000 to 3500 feet. 

Tuesday will be partly to mostly sunny.   Wednesday a weak low pressure area will move through Northern California (see map below) with light rain over the foothills and mountains and a few showers in the valley.  Snow levels will be 5000 feet north and 6000 feet south.  

Thursday through the weekend we will have a weak high pressure ridge along the coast.  This will push the jetstream northward.   The northstate will see partly to mostly sunny skies with a few clouds at times from storms moving by to our north.  Temperatures will be normal to a few degrees above normal. 

The Old Forecaster

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Wednesday, April 11, 2018

Weather Discussion for Wednesday April 11, 2018

Normal high and low temperatures for April 9-April 16  (high/low) Redding 71/46, Chico 72/45, Quincy 64/32, Chester 57/29, Susanville 62/32, Grass Valley 62/39, Weaverville 67/34, Mt. Shasta 59/ 33, Yreka 63/34, Alturas 60/28

This blog will be issued every Monday, Wednesday, and Saturday morning and updated if the weather is changing or critical or interesting weather events are occurring.

Not a lot of change in the large scale weather pattern for the next week  We will continue to see fast moving low pressure troughs and frontal systems move across our area every 2 to 3 days. 

The next frontal system is approaching the coast.  This system will spread light rain over Northern California later today and tonight.  The precipitation will turn to showers Thursday morning and decrease during the day.  This system is slightly colder and snow levels will drop to around 5000 feet by early Thursday. Gusty south winds will occur this afternoon and evening. 

Late Thursday afternoon, Friday and Saturday we will see partly to mostly sunny skies with near normal temperatures.  

Sunday another low pressure area will be along the coast (see map below).  This system will bring rain to the north state Sunday with showers on Monday.  Snow levels will start out high but drop to 3500 to 4000 feet in the north by Sunday evening.  

Tuesday we will have a break and then another low pressure trough will move through Wednesday afternoon and Thursday.

The Old Forecaster

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Monday, April 9, 2018

Weather Discussion for Monday April 9, 2018

Normal high and low temperatures for April 9-April 16  (high/low) Redding 71/46, Chico 72/45, Quincy 64/32, Chester 57/29, Susanville 62/32, Grass Valley 62/39, Weaverville 67/34, Mt. Shasta 59/ 33, Yreka 63/34, Alturas 60/28

This blog will be issued every Monday, Wednesday, and Saturday morning and updated if the weather is changing or critical or interesting weather events are occurring.

Ref the question from the comments...The last storm came from the west but merged with a large area of subtropical moisture from the southwest.  This is called by some folks the "pineapple connection" or an "atmospheric river".

Clouds will start increasing later today and tonight as the next low pressure trough and frontal system approaches the coast.  We are still in a weather pattern, and will stay there for the next week, where the jetstream runs across the Pacific and over Northern California.  The Tuesday system will bring light rain to Northern California with snow levels 6000 feet or higher.   It will be followed by a slightly stronger storm on Wednesday with snow levels dropping to around 5000 feet in the north (see map below).  Thursday we will have partly cloudy skies with a few showers mainly over the higher elevations. 

Friday and most of Saturday the north state will be sunny with above normal temperatures and then Sunday and Monday the next storm reaches the coast. 

The Old Forecaster

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