Climate of Vallhyn

See also: Atmosphere of Planet V The climate of the Vallhyn varies due to differences in latitude, and a range of geographic features, including mountains and deserts. To the west, much of the continent is semi-arid to arid. To the east, the climate is humid continental in the northern areas (locations above 40 °N  latitude), to humid temperate in the central and middle coastal regions, to humid subtropical in the south. Higher-elevation areas of the Vallhyn Cordillera  are alpine. The climate along the southwestern coast is Mediterranean, while upper west coast areas are cool temperate oceanic. Northern portions of the continent are largely subarctic, with a cool oceanic climate along portions of the coast, and a polar climate in the north.

Continental Overview
As in most land masses located in the middle and lower-middle latitudes, the primary drivers of weather are the seasonal change in the solar angle, the migration north/south of the subtropical highs, and the seasonal change in the position of the polar and subtropical jet streams.

In the summer, the a semi-permanent high over the subtropical eastern ocean typically sends warm, humid air over the eastern, southern and central Vallhyn - resulting in  southwesterly airflow, stable conditions and cool to mild conditions. In summer, high pressure over the south-central western ocean typically results in northeasterly  airflow, warm to hot temperatures, high humidity and occasional thunderstorm activity for the southwestern coastline. The subtropical jet also brings in moisture from the southwest onto the arid steppes, resulting in a seasonal wet monsoon.

 In the winter, the subtropical highs retreat southward. The polar jet stream (and associated conflict zone between cold, dry air masses from the north and warm, moist air masses from the south) drops further southward - bringing major rain, ice and snow events, and much more variable, and sometimes dramatically colder, temperatures to central and western Vallhyn. Areas in the eastern region (the Kingdom of Grammen) however, often have more stable weather, as the Vallhyn Cordillera limits the polar jet stream’s impacts.

 Weather systems, be they high-pressure systems (cyclones), low-pressure systems (anticyclones) or fronts (boundaries between air masses of differing temperature, humidity and most commonly, both) are faster-moving and more intense in the winter/colder months than in the summer/warmer months. The eastern ocean is the origination area of many storms that enter the Vallhyn. Such "North Ocean lows" enter Vallhyn through the northeast, then move westward along the Vallhyn Cordillera, and central plains. They can generate unusually large temperature contrasts, and often bring copious moisture westward, resulting sometimes in cold conditions and possibly-heavy snow or ice north and west of the storm track, and warm conditions, heavy rains and potentially-severe thunderstorms south and east of the storm track - often simultaneously. Across the northern regions in winter (usually north and west of the Vallhyn Cordillera), "clipper" storms can be frequent, usually bringing light to moderate snowfalls, but often, windy and severe Arctic outbreaks behind them.

 In the cold season, most precipitation occurs in conjunction with organized low-pressure systems and associated fronts, especially in the east-central, eastern and southeastern regions. Average winter-season precipitation is especially heavy along the eastern mountain ranges. In the summer, storms are much more localized, with short-duration thunderstorms common in many areas east of the 100th meridian. In the warm season, storm systems affecting a large area are less frequent, and weather conditions are more solar (sun) controlled, with the greatest chance for thunderstorm and severe weather activity during peak heating hours.From late summer into fall, tropical cyclones sometimes approach or, more rarely, cross the southwestern regions, bringing high winds, heavy rainfall, and storm surges (often topped with battering waves) to coastal areas.

Regional Overview
Eastern Region Consisting of the Kingdom of Grammen and lined by the Vallhyn Cordillera to the north and west, the eastern half of Vallhyn is generally temperate. The mountain ranges block cold continental air from dipping southward and traps a majority of any precipitation via the rain-shadow effect. As such, the eastern region enjoys stable weather patterns and severe weather is relatively rare.

In the winter, the region enjoys  average daytime temperatures up to 66 °F ( 17.4 R) in the southernmost areas, and 33 °F ( 7.79 R) by the northern mountain range. In the mountains, it is not uncommon for average temperatures to remain below 10 °F ( 1.08 R) for the duration of the season and beyond. During the summer, this can rise past 93 °F ( 25.3 R) in southern locations and down to 35 °F ( 8.37 R) in the mountains.

Precipitation is also plentiful, though more falls along the coast and along the southern sections of the northern mountain range. During the winter months, snowfall in high-elevation areas can easily top 40 feet in the eastern mountains, edging off to a respectable 14 feet to the west. Some peaks remain snow-covered in the warm season and avalanches have claimed lives throughout the year. Snowfall is less likely outside of the mountains, with much of the region enjoying cold rain in its stead. Along the coast, rainfall rates can be in excess of 50 inches, giving rise to flooding concerns. In the western portions of the region, however, this drops to a more manageable 30 inches.

During the summer, some mountain regions will continue to get fresh snowfall, even into the summer months. Precipitation generally decreases in the south, as the polar jet stream shifts northward. As northern areas can get up to 60 inches of rain, combined with snowmelt, flooding can be catastrophic and widespread. Furthermore, thunderstorms have led to several deaths due to lightning strikes.

Flooding and lightning aside, other weather natural disasters are relatively uncommon. Due to atmospheric circulations and oceanic temperatures, this region is not conducive to tropical cyclone formation, though there exists records of a couple of weak systems making landfall along the far southwest coastline. While tornadoes are next to unheard of, landspouts have been reported in the western area, though never strong or long-lived. Waterspouts are also sighted on occassion along the southern coast.

Southwestern Region
Consisting of mostly arid and semi-arid environments, this region has great variability in its weather conditions.

During the winter, this region gets chilly, with eastern, coastal areas getting average daytime temperatures of 50 °F (12.7 R)  to below 20 °F (4 R)  in the interior. During the summer, daytime highs can rise in excess of 115 °F  (31.7 R). This region holds the continental record for the widest range between daytime and nighttime temperatures (79.8 degrees).

The region is light on precipitation due to several factors. Most storms arrive in the area after losing a majority of the moisture along the continent. The area also suffers from the rain shadow effect due to the high cliffs along the southern and eartern coasts. These high cliffs prevent most of the moisture from reaching the region.

As such, the region experiences two bumps from which it receives most of its annual rainfall: the winter precipitation when the polar jet stream dips southward and the summer wet monsoon. During the summer months, a surface low pressure system forms in the northern portion of the region, drawing in moisture from the west and providing much needed rainfall. During the winter, the region generally gets up to 1.5 inches of rainfall; during the wet monsoon season, this can be in excess of 9 inches on a good year. The wet monsoon season generally begins in the western section before shifting eastward over a several week's time. Daily airmass thunderstorms are common for the following month or two before the surface pressure system slowly falls apart as autumn moves in.

During the summer months, sandstorms are not uncommon. In the slightly more moist eastern section of the region, tornadoes have been recorded on multiple occassions, with one measured with winds of at least 200 mph, remaining on the ground for over 30 minutes and affecting at least three caravans. These storms tend to move to the northwest. The region is also affects by the occassional Nor'wester, a macro-scale storm affecting the entire western seaboard. These storms generally form to the west of the continent, moving north along the coast. Generally happening during the autumn and winter months, these storm systems bring strong winds and heavy rains to the western areas, as well as heavy snowfall in the mountains. Still, the dry heat is the regions worst killer, claiming dozens of lives every year.

Northwestern Region
This region remains cool throughout the year, with winter daytime temperatures averaging at 20 °F (4 R)  and below. In the summer, temperatures rarely rise above 80 <span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">°F (21.5 R).

Similarly, rainfall is rare, with many years only receiving less than an inch of rain. Some locations to the southwest benefit from Region B's wet monsoon season, but the mountain range between the two regions prevents much.

This region is most at risk to severe drought, as well as the high winds and bitter cold of any Nor'westers. The area is also susceptible to massive windstorms, which give way to sandstorms that can scour across the entire region.

Northern Region
This region keeps to the northern chunk of the continent. It  is cold throughout the year, rarely rising over 70 <span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">°F (18.6 R)  in the summer, and regularly dipping below 0 <span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">°F  (-01.83 R) in the winter.

This region is also dry, only getting about 40 inches annually, most of which arrives in the summer.

Portions of this area can be incredibly windy.

Extremes
<span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">In the northern region, <span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">  tundra<span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">  <span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">and <span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">  arctic<span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">  <span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">conditions predominate, and the temperature has fallen as low as −80 °F (−25.16 R). <sup class="reference" id="cite_ref-11" style="color:rgb(37,37,37);font-family:sans-serif;line-height:1;unicode-bidi:-webkit-isolate;font-size:11.1999998092651px;">[11] <span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">  <span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">On the other end of the spectrum, <span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">  a location in the southwestern region<span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">  <span style="color:rgb(37,37,37);font-family:sans-serif;line-height:22.3999996185303px;">once reached 128.3°F (34.2 R).

<p style="margin-top:0.5em;margin-bottom:0.5em;line-height:22.3999996185303px;color:rgb(37,37,37);font-family:sans-serif;">On average, the mountains of the Sky Islands receive the highest levels of snowfall and rainfall. <span style="line-height:22.3999996185303px;color:rgb(58,58,58);font-family:Helvetica,Arial,sans-serif;">This mountain range holds the records for most annual snowfall (73.5 feet), most annual rainfall (1,186.3 inches), and highest rainfall in 24 hours (27.4 inches). Meanwhile, the nortwestern region holds the record for least rainful, having a yearly average of less than 1 inch of rain, and regularly going up to 9 years without measureable precipitation.